What does sure mean?
Sure is a flexible English word that can express certainty, confidence, emphasis, or agreement. As an adjective, it means that someone is confident a statement is true or an outcome will occur: “Are you sure?” As an adverb, it means certainly or without doubt and can emphasize a following word. As an informal interjection, “Sure!” conveys assent, acknowledgment, or willingness. These meanings are related because the word originally described being free from doubt or fear. In everyday use, sure often sounds more conversational than definite or certain, especially in an answer to a suggestion or request. Its certainty can also be weakened politely: “I’m not sure” communicates uncertainty without sounding blunt. Sure works as an intensifier in informal phrases like “sure fast,” while constructions such as “make sure” and “pretty sure” are common in both spoken and written English. Its value is flexibility: one compact word can qualify confidence, strengthen an assertion, or provide a quick response, with register helping determine the intended force.
Certain or confident about a fact, outcome, or choice; also reliable or dependable.
"We need a sure method for finding the error."
Common constructions include sure of something, sure that something is true, and sure to do something.
Certainly or without doubt; emphatically or unmistakably.
"The issue is sure to be raised at the meeting."
Informal constructions such as “sure fast” and “sure enough” are especially common in speech.
An informal expression of agreement, acknowledgment, or willingness.
"“Can you check the report?” — “Sure, I'll do it now.”"
This use is common in casual conversation but may be unsuitable in highly formal settings.
Sure originally meant safe: it came from a Latin word literally meaning “free from care.”
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does sure come from?
The word entered Middle English from Old French seur, meaning “secure” or “safe,” and was ultimately borrowed from Latin securus. Securus was formed from se-, meaning “apart,” and cura, meaning “care,” literally conveying “free from care”; its English development narrowed the sense toward certainty and confidence. The same Latin roots produced secure, security, care, and cure, reflected in the cognates listed above.
Related word forms
How sure is actually used
The adjective commonly takes of before a noun or subject and that before a clause. In informal English, sure can also intensify a following adjective or adverb. The interjection is especially common in friendly or service-oriented conversation and may sound overly casual in formal settings.
Easily confused with sure
Sure means certain or confident, while a shore is the land beside a body of water.