What does certain mean?
Certain is one of the most versatile adjectives in English, carrying two main senses. First, it means completely sure or free from doubt, as when we say we are certain of a fact or feel certain about a decision; in this use it signals confidence and conviction. Second, it describes something fixed, established, or inevitable, as in 'a certain winner' or 'certain death.' A third common function is vaguer: placed after 'a' or 'some', certain refers to a particular but unnamed person or thing, softening a statement or preserving discretion, as in 'a certain reluctance.' The word derives from the Latin certus, meaning settled or determined, and entered English through Old French. Its derivatives certainly and certainty are among the most frequent expressions of assurance in everyday English, making certain essential for expressing both confidence and tactful imprecision.
Sure to happen or be true; incapable of being doubted or disputed.
"Victory seemed certain until the final minutes of the match."
Often intensified by 'absolutely' or 'quite' when expressing personal conviction.
Used with 'a' to indicate a specific but unnamed or unquantified person, thing, or degree.
"The announcement was met with a certain amount of skepticism."
Used to refer to people or things that are particular but not specified, usually in the phrase 'certain of' or 'certain ones'.
"Certain of the guests arrived early."
"Certain" comes from the Latin certus, meaning "settled or fixed" — the same root that gives us "certify" and even "concert," which originally meant agreeing together.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of certain
Certain comes from the Latin certus, meaning 'settled, resolved, or fixed,' itself derived from the verb cernere, 'to decide or determine.' It passed into English via Old French certain during the Middle Ages, replacing native expressions for assuredness. The same Latin root produced cognates such as certify, ascertain, and certitude, all sharing the core idea of something made sure or decided.
Related word forms
How certain is actually used
Certain is standard across registers, from casual speech to formal writing. In the sense 'particular but unnamed,' it usually follows an indefinite article ('a certain hesitation'), whereas the sense of confidence typically follows a linking verb ('she was certain').
Easily confused with certain
A curtain is a piece of cloth hung to cover a window or divide a room, while certain means sure or particular — the words sound nearly identical in many British accents but share nothing in meaning.
Uncertain is simply the direct opposite of certain, meaning not known or not definite.