sure, certain, positive, cocksure mean having no doubt or uncertainty. sure usually stresses the subjective or intuitive feeling of assurance. certain may apply to a basing of a conclusion or …

CERTAIN definition: 1. having no doubt or knowing exactly that something is true, or known to be true, correct, exact…. Learn more.

1. (postpositive) positive and confident about the truth of something; convinced: I am certain that he wrote a book. 2. (usually postpositive) definitely known: it is certain that they were on the bus. 3. …

If you are certain about something, you firmly believe it is true and have no doubt about it. If you are not certain about something, you do not have definite knowledge about it.

Jan 20, 2026 · certain (comparative more certain or certainer, superlative most certain or certainest) Sure in one's mind, positive; absolutely confident in the truth of something.

Certain can mean "definite" or "sure to happen," like getting wet, a certain outcome of not having an umbrella in a rainstorm. It can also refer to a particular person or thing.

certain meaning, definition, what is certain: confident and sure, without any doubts: Learn more.

Sure: with an infinitive: as, he is certain to be there to-morrow. Synonyms Undeniable, unquestionable, undoubted, indubitable, indisputable, incontrovertible, inevitable.

Definition of certain adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

CERTAIN meaning: 1. having no doubt or knowing exactly that something is true, or known to be true, correct, exact…. Learn more.