from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Confident, as of something awaited or expected.
  • adjective Impossible to doubt or dispute; certain.
  • adjective Bound to come about or happen; inevitable.
  • adjective Having one's course directed; destined or bound.
  • adjective Certain not to miss, slip, or err; steady.
  • adjective Not hesitating or wavering; firm.
  • adjective Worthy of being trusted or depended on; reliable.
  • adjective Free from or marked by freedom from doubt.
  • adjective Careful to do something.
  • adjective Obsolete Free from harm or danger; safe.
  • adverb Surely; certainly.
  • idiom (for sure) Certainly; unquestionably.
  • idiom (make sure) To establish something without doubt; make certain.
  • idiom (sure enough) As one might have expected; certainly.
  • idiom (to be sure) Indeed; certainly.

from The Century Dictionary.

  • To assure; make certain.
  • Confident; undoubting; having no fear of being deceived or disappointed.
  • Certain of one's facts, position, or the like; fully persuaded; positive.
  • Certain to find or retain: with of: as, to be sure of success; to be sure of life or health.
  • Fit or worthy to be depended on; capable of producing a desired effect or of fulfilling requisite conditions; certain not to disappoint expectation; not liable to failure, loss, or change; unfailing; firm; stable; steady; secure; infallible.
  • Certain to be or happen; certain.
  • Undoubted; genuine; true.
  • Out of danger; secure; safe.
  • Engaged to marry; betrothed.
  • See to be sure, below.
  • To make fast by betrothal; betroth.
  • Synonyms and Certain, Positive, etc. See confident.
  • Certainly; without doubt; doubtless; surely.
  • Firmly; securely.

from the GNU version of the Collaborative International Dictionary of English.

  • adverb In a sure manner; safely; certainly.
  • adjective Certainly knowing and believing; confident beyond doubt; implicity trusting; unquestioning; positive.
  • adjective Certain to find or retain.
  • adjective Fit or worthy to be depended on; certain not to fail or disappoint expectation; unfailing; strong; permanent; enduring.
  • adjective obsolete Betrothed; engaged to marry.
  • adjective Free from danger; safe; secure.
  • adjective certainly; without doubt; as, Shall you do? To be sure I shall.
  • adjective [Obs.] To betroth.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective Physically secure and certain, non-failing, reliable.
  • adjective Certain in one's knowledge or belief.
  • adjective Certain to act or be a specified way.
  • adverb Without doubt.
  • interjection this sense) Yes, of course.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adverb definitely or positively (`sure' is sometimes used informally for `surely')
  • adjective infallible or unfailing
  • adjective reliable in operation or effect
  • adjective physically secure or dependable


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English, from Old French, safe, from Latin sēcūrus; see secure.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English sure, sur, from Middle French sur, from Old French seür, from Latin sēcūrus ("secure", literally "carefree"), from se ("apart") + cura ("care") (compare Old English orsorg ("carefree"), from or ("without") + sorg ("care")). See cure. Displaced native Middle English wis, iwis ("certain, sure") (from Old English ġewis, ġewiss ("certain, sure")), Middle English siker ("sure, secure") (from Old English sicor ("secure, sure")).


Help support Wordnik (and make this page ad-free) by adopting the word sure.


  • The problem with most "act now, just in case" demands and figuring that the "just in case" is considered a lie to suck in the skeptics... there is no "in case" because it's a sure thing is that the changes either won't do what they supposedly are supposed to do or would actually make it worse *and* that every "solution" invariably will cause *for sure* harm to economies and real people will suffer.

    "Let's just say that global warming deniers are now on a par with Holocaust deniers...." Ann Althouse 2008

  • I'm not sure that the two gents, hot as they are, qualify as "younger" but it seems the "hipster" part is covered by the Loverboy t-shirt, worn, I'm *sure*, in a "Hahahaha, they're so bad, they're good" kind of ironic way.

    Meredith Monk and The Integrals sfmike 2008

  • Is yet one more reason beyond what I blogged why I am just not so sure even good enough moms like me will be *for sure* going to Heaven.

    Heaven Can Wait 2007

  • "I warn't sure, sir," faltered Nance, whose honor had outweighed her longing for money and the comfort it would bring, and had brought her through the long city to seek the rightful owner of the thimble -- "I warn't _sure_; but I knew her name, for herself an 'a gennelman came onst to see mother long ago."

    Harper's Young People, February 24, 1880 An Illustrated Weekly Various

  • Work your way up during these five years into Mr. Van Ostend's confidence, and I am sure, _sure_, that by that time he will have something for you that will satisfy even your young ambition.

    Flamsted quarries Mary E. Waller

  • "I'm sure he will, little sweetheart I'm _sure_ he will."

    A Fool There Was Porter Emerson Browne

  • "You are sure he is married, Sara, -- _quite sure_?"

    The Hermit of Far End Margaret Pedler

  • Even now, I can't be sure you love me -- not _sure!

    Nocturne Frank Swinnerton 1933

  • _ That's the word I found to say it; she's sure -- sure -- _sure!

    King Coal : a Novel Upton Sinclair 1923

  • "Father Davy, are you sure, _sure_?" begged his daughter.

    Under the Country Sky Frances [Illustrator] Rogers 1912


Log in or sign up to get involved in the conversation. It's quick and easy.