This list includes 29 SAT words that start with O, from “obdurate” to “overwrought”. Many are formal or literary words you can use in essays and reading-comprehension passages.
SAT words that start with O are high-value vocabulary items beginning with O used on tests and in academic writing. Many derive from Latin roots, and writers use them for precise tone or emphasis.
Below you’ll find the table with Word, Difficulty, Definition and Example sentence.
Word: The vocabulary entry itself; you see the exact spelling so you can recognize and practice the word.
Difficulty: A quick easy/medium/hard tag to help you prioritize which words you should study first for tests.
Definition: A concise dictionary-style line that explains the word meaning so you can grasp and recall it quickly.
Example sentence: One clear sentence showing typical usage so you understand context and can model similar sentences.
SAT words that start with O
| Word | Part of speech | Difficulty | Example sentence |
|---|---|---|---|
| obdurate | adjective | Hard | The obdurate politician refused to compromise on the bill. |
| obfuscate | verb | Hard | The witness tried to obfuscate the truth with irrelevant details. |
| oblique | adjective | Medium | She made an oblique reference to his recent troubles. |
| oblivious | adjective | Easy | He was oblivious to the quiet concerns of his friends. |
| obsequious | adjective | Hard | The obsequious assistant agreed with everything his boss said. |
| obsolete | adjective | Easy | Typewriters are now considered obsolete technology. |
| obstinate | adjective | Medium | Her obstinate refusal to listen angered her parents. |
| obstreperous | adjective | Hard | The obstreperous crowd was difficult for the police to control. |
| obtuse | adjective | Medium | Please don’t be so obtuse; the answer is obvious. |
| occlude | verb | Hard | A fallen tree will occlude the road until it is moved. |
| officious | adjective | Hard | The officious bureaucrat insisted we fill out the forms again. |
| ominous | adjective | Medium | The ominous clouds on the horizon signaled a coming storm. |
| omnipotent | adjective | Medium | In the story, the genie was an omnipotent being. |
| omniscient | adjective | Medium | The novel is told from an omniscient third-person point of view. |
| onerous | adjective | Hard | The intern was assigned the onerous task of sorting the old files. |
| onus | noun | Medium | The onus is on the plaintiff to provide evidence for their case. |
| opaque | adjective | Medium | The opaque language of the legal document confused everyone. |
| opportune | adjective | Medium | It was an opportune moment to ask for a promotion. |
| opportunist | noun | Medium | The opportunist used the crisis to buy stocks at low prices. |
| opulence | noun | Hard | The opulence of the royal court was legendary. |
| opulent | adjective | Hard | He lived an opulent lifestyle in his mansion. |
| orator | noun | Easy | Winston Churchill was a gifted orator. |
| ornate | adjective | Medium | The ornate frame was covered in detailed gold carvings. |
| oscillate | verb | Medium | Public opinion tends to oscillate between two extremes. |
| ossify | verb | Hard | His ideas began to ossify as he grew older. |
| ostensible | adjective | Hard | His ostensible reason for the visit was business. |
| ostentatious | adjective | Hard | She wore an ostentatious diamond necklace to the party. |
| overt | adjective | Medium | He showed overt hostility toward his rival. |
| overwrought | adjective | Medium | She was too overwrought to continue the discussion calmly. |
Descriptions
obdurate
Stubbornly refusing to change one’s opinion or course of action; unyielding.
obfuscate
To deliberately make something unclear or confusing to conceal the truth.
oblique
Not straightforward or direct; indirect, slanting, or evasive.
oblivious
Unaware of or not concerned about what is happening around one.
obsequious
Overly obedient or attentive in a servile way to gain favor.
obsolete
No longer in use or produced; out of date.
obstinate
Stubbornly refusing to change one’s opinion despite persuasion; mulish.
obstreperous
Noisy, unruly, and difficult to control.
obtuse
Annoyingly insensitive or slow to understand; not sharp.
occlude
To stop, close up, or obstruct a passage or opening.
officious
Assertively offering unwanted help or advice; meddlesome.
ominous
Giving the impression that something bad or unpleasant is going to happen.
omnipotent
Having unlimited power; able to do anything.
omniscient
Knowing everything; having infinite awareness and understanding.
onerous
Involving a great deal of effort, trouble, or difficulty; burdensome.
onus
A duty, burden, or responsibility for something.
opaque
Not able to be seen through; not transparent. Figuratively, hard to understand.
opportune
Occurring at a particularly favorable or appropriate time; timely.
opportunist
A person who exploits circumstances to gain immediate advantage.
opulence
Great wealth or luxuriousness; lavishness.
opulent
Ostentatiously rich and luxurious or lavish.
orator
A skilled and eloquent public speaker.
ornate
Made in an intricate shape or decorated with complex patterns; elaborate.
oscillate
To swing back and forth; to vary between different beliefs or opinions.
ossify
To turn into bone; to become rigid or fixed in attitude or custom.
ostensible
Stated or appearing to be true, but not necessarily so; seeming.
ostentatious
Characterized by a vulgar or pretentious display; designed to impress.
overt
Done or shown openly; plainly or readily apparent, not secret.
overwrought
In a state of nervous excitement or anxiety; overly elaborate.