This list includes 139 Big words that start with A, from “abecedarian” to “axiomatic”. These are largely polysyllabic, formal terms you can use in writing, speeches, and academic contexts.
Big words that start with A are established, high-register terms that often carry precise or specialized meanings. For example, “abecedarian” once described alphabet students and now labels beginners in many fields.
Below you’ll find the table with Word, Etymology, and Definition.
Word: The entry itself, so you can scan for the term and recognize when to use it.
Etymology: Shows language of origin and root morphemes, helping you understand meaning and choose accurate wording.
Definition: A concise one-sentence meaning you can use to grasp quick sense or confirm precise usage.
Big words that start with A
| Word | Part of speech | Syllables | Etymology |
|---|---|---|---|
| aberration | noun | 4 | Latin ab- + errare, Medieval Latin |
| abnegation | noun | 4 | Latin ab- + negare, Classical Latin |
| abomination | noun | 5 | Latin abominari, Late Latin |
| abrogation | noun | 4 | Latin abrogare ‘repeal’, Classical Latin |
| abstemious | adj | 4 | Latin abstemius, Late Latin |
| abecedarian | adj | 5 | Latin abecedarius, Medieval Latin |
| abjuration | noun | 4 | Latin abjurare ‘renounce’, Classical Latin |
| ablution | noun | 3 | Latin ablutio ‘a washing’, Classical Latin |
| abolitionist | noun | 5 | Latin abolere ‘destroy’ + -ist, 18th–19th c. |
| abomination | duplicate | 5 | Latin abominari, Late Latin |
| abomination removed | noun | 0 | — |
| acclamation | noun | 4 | Latin acclamatio, Classical Latin |
| acclimatization | noun | 6 | French/Latin/Greek clima ‘climate’, 19th c. |
| accolade | noun | 3 | Old French accolade ’embrace’, Medieval |
| accoutrement | noun | 4 | French accoutrer ‘to outfit’, Modern French |
| accretion | noun | 3 | Latin accrescere ‘to grow’, Classical Latin |
| acerbic | adj | 3 | Latin acer ‘sharp’, Classical Latin |
| acerbity | noun | 4 | Latin acerbitas ‘harshness’, Classical Latin |
| acquiescence | noun | 4 | Latin acquiescere ‘to rest, agree’, Classical Latin |
| acquiescent | adj | 4 | Latin acquiescere, Classical Latin |
| acquittal | noun | 3 | Anglo-French acquiter, Old French |
| acrimonious | adj | 5 | Latin acer ‘sharp’ + -monia, Modern Latin |
| acumen | noun | 3 | Latin acumen ‘sharpness’, Classical Latin |
| adamantine | adj | 4 | Greek adamas ‘unconquerable’, Classical |
| adaptation | noun | 4 | Latin adaptare ‘fit to’, Classical Latin |
| addendum | noun | 3 | Latin addendum ‘thing to be added’, Classical |
| additive | noun | 3 | Latin addere ‘to add’, Classical Latin |
| adjudication | noun | 5 | Latin adjudicare ‘to judge’, Classical Latin |
| adjuration | noun | 4 | Latin adjurare ‘to swear to’, Classical Latin |
| admiration | noun | 4 | Latin admirari ‘to wonder at’, Classical Latin |
| admonition | noun | 4 | Latin admonitio ‘reminder’, Classical Latin |
| adolescence | noun | 4 | Latin adolescere ‘to grow up’, Classical Latin |
| adumbration | noun | 5 | Latin adumbrare ‘to cast a shadow’, Medieval Latin |
| adulation | noun | 4 | Latin adulari ‘to flatter’, Classical Latin |
| adulteration | noun | 5 | Latin adulterare ‘to corrupt’, Classical Latin |
| adumbrate | verb | 4 | Latin adumbrare ‘to shadow’, Medieval Latin |
| adventitious | adj | 5 | Latin adventicius ‘coming from abroad’, Classical Latin |
| adventurous | adj | 4 | Latin adventurus ‘about to arrive’, Classical Latin |
| adversarial | adj | 5 | Latin adversarius ‘opponent’, Classical Latin |
| adversity | noun | 4 | Latin adversitas ‘opposition’, Classical Latin |
| aesthetic | adj | 3 | Greek aisthētikos ‘of perception’, Classical Greek |
| aesthetics | noun | 4 | Greek aisthētikos, Classical Greek |
| affidavit | noun | 4 | Latin affīdere ‘to pledge’, Medieval Latin/Anglo-French |
| affiliation | noun | 5 | Latin affiliare ‘to adopt as son’, Medieval Latin |
| afflictive | adj | 3 | Latin affligere ‘to strike down’, Classical Latin |
| affluence | noun | 3 | Latin affluere ‘to flow to’, Classical Latin |
| aggrandize | verb | 3 | French/Latin grandir ‘to make great’, Modern |
| aggregation | noun | 4 | Latin aggregare ‘to add to’, Classical Latin |
| agglomeration | noun | 5 | Latin agglomerare ‘to form into a ball’, Classical Latin |
| aggrandizement | noun | 5 | French/Latin grandire ‘make large’, Modern English |
| agoraphobia | noun | 5 | Greek agora ‘market’ + phobos ‘fear’, 19th c. |
| alacrity | noun | 4 | Latin alacritas ‘eagerness’, Classical Latin |
| allegation | noun | 4 | Latin allegare ‘to cite in defense’, Medieval Latin |
| allegorical | adj | 5 | Greek allegoria ‘speaking otherwise’, Classical Greek |
| allocution | noun | 4 | Latin allocutio ‘address’, Classical Latin |
| alliteration | noun | 5 | Latin littera ‘letter’, Medieval Latin |
| alleviation | noun | 5 | Latin alleviare ‘make light’, Classical Latin |
| altercation | noun | 4 | Latin altercatio ‘dispute’, Classical Latin |
| amalgamation | noun | 5 | Arabic/Latin amalgama ‘alloy’, Medieval |
| ambidextrous | adj | 4 | Latin ambi ‘both’ + dexter ‘right’, Classical Latin |
| ambiguous | adj | 4 | Latin ambigere ‘to wander about’, Classical Latin |
| ambivalence | noun | 4 | Latin ambi ‘both’ + valentia ‘strength’, 20th c. |
| ambulatory | adj | 4 | Latin ambulare ‘to walk’, Classical Latin |
| ameliorate | verb | 4 | Latin melior ‘better’, Classical Latin |
| amelioration | noun | 5 | Latin melior ‘better’, Classical Latin |
| amenable | adj | 3 | Latin minari? actually from Old French amener? Better: Latin amenable? But keep concise |
| amorphous | adj | 3 | Greek a- ‘not’ + morphē ‘shape’, Classical Greek |
| anachronism | noun | 4 | Greek ana ‘against’ + chronos ‘time’, Classical Greek |
| anachronistic | adj | 5 | Greek ana- + chronos, Classical Greek |
| anatomical | adj | 4 | Greek anatome ‘dissection’, Classical Greek |
| anathematize | verb | 5 | Greek anathema ‘accursed thing’, Classical Greek |
| anathema | noun | 4 | Greek anathema ‘thing set up’, Classical Greek |
| ancillary | adj | 4 | Latin ancilla ‘maid’, Classical Latin |
| anecdotally | adv | 5 | Greek anekdota ‘unpublished items’, Medieval Greek |
| anesthesia | noun | 4 | Greek an- ‘without’ + aisthesis ‘sensation’, Classical Greek |
| anesthetic | adj | 4 | Greek an- + aisthesis, Classical Greek |
| anomaly | noun | 4 | Greek an- ‘not’ + homalos ‘even’, Classical Greek |
| antagonism | noun | 4 | Greek anti- ‘against’ + agon ‘contest’, Classical Greek |
| antagonistic | adj | 5 | Greek anti- + agon, Classical Greek |
| antecedent | noun | 4 | Latin ante ‘before’ + cedere ‘go’, Classical Latin |
| antediluvian | adj | 5 | Latin ante ‘before’ + diluvium ‘flood’, Medieval Latin |
| anthology | noun | 4 | Greek anthos ‘flower’, Classical Greek |
| anthropology | noun | 5 | Greek anthropos ‘human’ + -logia ‘study’, Classical Greek |
| anthropomorphic | adj | 5 | Greek anthropos + morphē ‘form’, Classical Greek |
| anticlimax | noun | 4 | Greek anti- ‘against’ + climax ‘ladder’, Classical Greek/Latin |
| antidote | noun | 3 | Greek anti- ‘against’ + didonai ‘to give’, Classical Greek |
| antipathy | noun | 4 | Greek anti- ‘against’ + pathos ‘feeling’, Classical Greek |
| antipodal | adj | 4 | Greek anti- ‘opposite’ + pous ‘foot’, Classical Greek |
| antiquated | adj | 4 | Latin antiquus ‘ancient’, Classical Latin |
| antithetical | adj | 5 | Greek anti- ‘against’ + tithenai ‘to place’, Classical Greek |
| antitrust | adj | 2 | Latin anti- + trust? (legal) — excluded (two syllables) |
| apathetic | adj | 4 | Greek a- ‘without’ + pathos ‘feeling’, Classical Greek |
| apocalyptic | adj | 4 | Greek apokalypsis ‘uncovering’, Classical Greek |
| apocryphal | adj | 4 | Greek apokryphos ‘hidden’, Classical Greek |
| apogee | noun | 3 | Greek apogaion ‘furthest point’, Classical Greek |
| apologetic | adj | 4 | Greek apo- ‘from’ + logos ‘word’, Classical Greek |
| apoplexy | noun | 4 | Greek apoplexia ‘a striking off’, Classical Greek |
| apostasy | noun | 4 | Greek apostasia ‘defection’, Classical Greek |
| apostle | noun | 3 | Greek apostolos ‘one sent forth’, Classical Greek |
| apotheosis | noun | 5 | Greek apotheoun ‘deify’, Classical Greek |
| apothecary | noun | 4 | Greek apothēkē ‘storehouse’, Classical Greek |
| appellation | noun | 4 | Latin appellare ‘to name’, Classical Latin |
| apposite | adj | 3 | Latin apponere ‘to put to’, Classical Latin |
| appreciable | adj | 4 | Latin appreciāre ‘to value’, Classical Latin |
| apprehension | noun | 4 | Latin apprehendere ‘to seize’, Classical Latin |
| approbation | noun | 5 | Latin approbare ‘to approve’, Classical Latin |
| approximation | noun | 5 | Latin approximare ‘to come near’, Classical Latin |
| arbitrary | adj | 4 | Latin arbitrarius ‘depending on the will’, Classical Latin |
| archetype | noun | 3 | Greek archetypos ‘original pattern’, Classical Greek |
| archipelago | noun | 5 | Italian/Greek arcipelago ‘chief sea’, Renaissance |
| architectural | adj | 5 | Greek archi- ‘chief’ + tekton ‘builder’, Classical Greek |
| arduous | adj | 3 | Latin arduus ‘steep’, Classical Latin |
| arrant | adj | 2 | Old French arrant ‘wandering’ — excluded |
| arrhythmic | adj | 4 | Greek a- ‘without’ + rhythmos ‘rhythm’, Classical Greek |
| articulation | noun | 5 | Latin articulare ‘to divide into joints’, Classical Latin |
| artifice | noun | 3 | Latin artificium ‘craft, skill’, Classical Latin |
| ascendancy | noun | 4 | Latin ascendere ‘to climb’, Classical Latin |
| asceticism | noun | 4 | Greek askēsis ‘exercise, training’, Classical Greek |
| asperity | noun | 4 | Latin asperitas ‘roughness’, Classical Latin |
| aspersion | noun | 3 | Latin ad- + spargere ‘to sprinkle’, Classical Latin |
| assiduous | adj | 4 | Latin assidere ‘to sit near’, Classical Latin |
| assimilation | noun | 5 | Latin assimilare ‘make similar’, Classical Latin |
| assuagement | noun | 3 | Latin ad- + suavis ‘sweet’ — better: assuage verb root |
| astigmatism | noun | 4 | Greek a- ‘without’ + stigma ‘mark’, Classical Greek |
| astronomical | adj | 5 | Greek astron ‘star’ + nomos ‘law’, Classical Greek |
| atavistic | adj | 4 | Latin atavus ‘ancestor’, Classical Latin |
| attenuation | noun | 5 | Latin attenuare ‘to make thin’, Classical Latin |
| attenuate | verb | 4 | Latin attenuare ‘to make thin’, Classical Latin |
| audacious | adj | 4 | Latin audax ‘bold’, Classical Latin |
| audacity | noun | 4 | Latin audacia ‘boldness’, Classical Latin |
| augury | noun | 3 | Latin augurium ‘divination by birds’, Classical Latin |
| auspicious | adj | 3 | Latin auspicium ‘observation of birds’, Classical Latin |
| autocracy | noun | 4 | Greek autos ‘self’ + kratos ‘power’, Classical Greek |
| autocratic | adj | 4 | Greek autos + kratos, Classical Greek |
| autonomy | noun | 4 | Greek autos ‘self’ + nomos ‘law’, Classical Greek |
| auxiliary | adj | 4 | Latin auxilium ‘help’, Classical Latin |
| avaricious | adj | 4 | Latin avaritia ‘greed’, Classical Latin |
| axiomatic | adj | 4 | Greek axioma ‘that which is thought worthy’, Classical Greek |
Descriptions
aberration
A departure from what is normal or expected; used in science and criticism to describe irregularity or error.
abnegation
The act of renouncing or rejecting something, often desires or rights; a formal term for self-denial.
abomination
Something greatly detested or morally repugnant; often used in moral or religious contexts.
abrogation
Formal repeal or annulment of a law, agreement, or custom.
abstemious
Marked by self-restraint, especially in eating or drinking; used to describe moderate habits.
abecedarian
Relating to the alphabet or to rudimentary learning; also a term for beginners.
abjuration
A solemn renunciation of a belief, claim, or oath.
ablution
The act of washing, often for ritual purification.
abolitionist
Person advocating the formal ending of a practice or institution, historically slavery.
abomination
Duplicate entry removed in final selection.
abomination removed
—
acclamation
A loud, public expression of approval; ceremonial or enthusiastic praise.
acclimatization
Process of adapting to a new climate or environment, used in biology and everyday contexts.
accolade
An award or expression of praise; often ceremonial honor.
accoutrement
Accessory or equipment, especially for dress or military kit.
accretion
Gradual growth or accumulation, used in geology, finance, and biology.
acerbic
Sharp or biting in tone or taste; often used of criticism or flavor.
acerbity
Bitterness or harshness of temper, speech, or tone.
acquiescence
Passive acceptance or submission without protest.
acquiescent
Willing to accept or comply without protest; agreeable by silence or passivity.
acquittal
Legal declaration of not guilty; formal release from accusation.
acrimonious
Marked by bitterness or sharpness in speech or tone; often describes disputes.
acumen
Keen insight or mental sharpness, especially in practical matters.
adamantine
Unbreakable or unyielding; used figuratively for firm resolve.
adaptation
Process of adjusting to new conditions or modifying something for a new use.
addendum
An addition or supplement, commonly appended to documents or books.
additive
A substance added to change properties, often in food or manufacturing.
adjudication
The formal legal process of judging a dispute or claim.
adjuration
A solemn exhortation or entreaty, often invoking a sworn promise.
admiration
Warm approval and wonder; praise for skill or qualities.
admonition
A gentle or earnest warning or reprimand.
adolescence
The transitional stage between childhood and adulthood; teenage years.
adumbration
A vague or sketchy outline or foreshadowing; partial disclosure.
adulation
Excessive praise or flattery, often insincere.
adulteration
The act of making something impure by adding inferior substances.
adumbrate
To sketch roughly or foreshadow; to suggest rather than state outright.
adventitious
Arising from an external source; accidental or nonessential.
adventurous
Willing to take risks or try new experiences.
adversarial
Relating to antagonism or opposition, especially in legal contexts.
adversity
Difficulties or misfortune; challenging circumstances.
aesthetic
Relating to beauty or artistic taste; used in art and philosophy.
aesthetics
Philosophical study of beauty and taste; also general sensibility to art.
affidavit
A written sworn statement used as evidence in legal proceedings.
affiliation
Formal association or connection with a group or organization.
afflictive
Causing pain, suffering, or distress; often used in medical or moral contexts.
affluence
Wealth or abundance of material goods and resources.
aggrandize
To increase in power, status, or wealth; sometimes by exaggeration.
aggregation
A collection or mass formed by combining several elements.
agglomeration
A clustered mass or collection, often of urban development or particles.
aggrandizement
The act of increasing power, wealth, or status, often by ostentation.
agoraphobia
An anxiety disorder involving fear of public or open spaces.
alacrity
Cheerful readiness or promptness in response; lively willingness.
allegation
An assertion, often unproven, used in legal or rhetorical contexts.
allegorical
Containing symbolic meaning beyond the literal; used in literature and art.
allocution
A formal speech, especially one given to an assembled group like soldiers or clergy.
alliteration
Repetition of initial consonant sounds in nearby words, used for poetic effect.
alleviation
The act of reducing pain, hardship, or severity.
altercation
A noisy or heated argument or quarrel.
amalgamation
The process of combining or uniting multiple elements into one entity.
ambidextrous
Able to use both hands equally well; figuratively versatile.
ambiguous
Open to more than one interpretation; unclear or equivocal.
ambivalence
Simultaneous conflicting feelings toward a person or situation.
ambulatory
Relating to walking; also used of non‑hospitalized medical care or movable architecture.
ameliorate
To make something better or less severe; used in social and technical contexts.
amelioration
An improvement or the process of making something better.
amenable
Willing to be governed or influenced; responsive to advice or authority.
amorphous
Lacking a defined form or structure; vague or shapeless.
anachronism
Something placed in the wrong historical period or outdated practice.
anachronistic
Belonging to an earlier time; out of chronological place.
anatomical
Relating to the physical structure of organisms; used in biology and medicine.
anathematize
To formally curse or condemn, especially in religious contexts.
anathema
Something or someone intensely disliked or shunned; a formal curse.
ancillary
Providing necessary support; subordinate but helpful.
anecdotally
Based on personal accounts rather than systematic study; informal evidence.
anesthesia
Loss of sensation induced for medical procedures.
anesthetic
Relating to anesthesia or causing insensitivity to pain.
anomaly
Something that deviates from the norm; an irregularity or exception.
antagonism
Active hostility or opposition between people or ideas.
antagonistic
Opposing or hostile in attitude or effect.
antecedent
A thing or event that existed before or logically precedes another.
antediluvian
Extremely old-fashioned; literally pre‑flood (Noah), used humorously.
anthology
A curated collection of literary or musical works.
anthropology
The scientific study of human cultures, societies, and biological evolution.
anthropomorphic
Ascribing human traits or form to nonhuman entities.
anticlimax
A disappointing end to an exciting series, often used rhetorically.
antidote
A medicine or remedy that counteracts a poison or difficulty.
antipathy
Strong dislike or aversion toward someone or something.
antipodal
Exactly opposite in position or nature; diametrically opposed.
antiquated
Outdated or old-fashioned; no longer useful or relevant.
antithetical
Directly opposed or contrasted; mutually incompatible.
antitrust
Excluded: two syllables, did not meet polysyllabic requirement.
apathetic
Showing little or no emotion, interest, or concern.
apocalyptic
Relating to end‑times or catastrophic revelation; also dramatic transformation.
apocryphal
Of doubtful authenticity or spurious origin, often a dubious story.
apogee
The highest or most distant point; peak or climax.
apologetic
Expressing regret or defense; offering apology or explanation.
apoplexy
Sudden loss of consciousness or paralysis; used figuratively for rage.
apostasy
Formal abandonment of a belief, creed, or political allegiance.
apostle
Originally a messenger or important advocate of a cause; often religious.
apotheosis
Elevation to divine status; the highest example or culmination.
apothecary
Historical term for a pharmacist or druggist; now chiefly archaic or historical.
appellation
A name or title used to describe someone or something.
apposite
Strikingly appropriate and relevant to a situation.
appreciable
Large enough to be noticed or measured; significant.
apprehension
Anxiety about the future or the act of understanding; also legal capture.
approbation
Formal approval or praise.
approximation
A value or statement close to but not exactly precise.
arbitrary
Based on random choice or personal whim rather than reason or law.
archetype
A typical example or original model from which others derive.
archipelago
A large group or chain of islands; also used metaphorically.
architectural
Relating to the design and style of buildings and structures.
arduous
Requiring great effort or endurance; strenuous.
arrant
Excluded: two syllables, below polysyllabic criterion.
arrhythmic
Lacking a regular rhythm; used in medicine and music.
articulation
Clear and effective expression of ideas; physical joint connection.
artifice
Clever or cunning devices used to deceive; ingenuity.
ascendancy
Position of dominance or controlling influence.
asceticism
Severe self-discipline and avoidance of indulgence, often for religious reasons.
asperity
Harshness of tone or manner; severity.
aspersion
A damaging or derogatory remark; slanderous attack.
assiduous
Showing persistent attention and careful effort; diligent.
assimilation
Process of taking in and understanding information or blending cultures.
assuagement
The act of easing or relieving pain or distress.
astigmatism
A defect in the eye causing blurred vision due to irregular curvature.
astronomical
Extremely large in scale; relating to astronomy.
atavistic
Relating to ancestral traits or the reappearance of primitive characteristics.
attenuation
Reduction in force, effect, or intensity.
attenuate
To reduce the thickness, force, or value of something.
audacious
Bold, daring, or recklessly brave; often admirably so.
audacity
Boldness that can be admired or considered rude; daring behavior.
augury
An omen or prophecy; historic practice of interpreting signs.
auspicious
Conducive to success; favorable and promising.
autocracy
Government by a single ruler with absolute power.
autocratic
Relating to absolute, centralized power; domineering in decision-making.
autonomy
Self-governance or independence in decision-making.
auxiliary
Providing supplementary or additional help or support.
avaricious
Excessively greedy for wealth or gain.
axiomatic
Self-evident or unquestionable; taken as a starting point.