adjective

certain

Translation

sure, convinced, specific, particular

I'm certain that he is right.

A certain person told me the secret.

It is certain to rain tomorrow.

((that ...)) to be sure that (sth.) will happen I'm certain that she will come.

((about sth.)) to be sure about (sth.) Are you certain about the date?

((to-inf)) to be sure to do (sth.) He is certain to pass the exam.

a certain ((noun)) a particular but unnamed (noun) A certain man was at the door.

Synonyms: sure, definite; Antonyms: uncertain, doubtful

From Latin 'certus' meaning 'sure, settled'.

Think of 'certify' - to make something certain.