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Alternative forms[edit]


onlesse, from on lesse, from "on a less condition" ("on" became un-).


  • IPA(key): /ənˈlɛs/, /ʌnˈlɛs/, /ɪnˈlɛs/
  • (file)
  • Rhymes: -ɛs



  1. Except on a specified condition; if not.
    I’m leaving unless I get a pay rise (AmE: raise).
    • 1839, Denison Olmsted, A Compendium of Astronomy Page 95
      Secondly, When a body is once in motion it will continue to move forever, unless something stops it. When a ball is struck on the surface of the earth, the friction of the earth and the resistance of the air soon stop its motion.
    • 1971, Dr. Seuss, The Lorax:
      Unless someone like you...cares a whole awful lot...nothing is going to get better...It's not.
  2. If not; used with counterfactual conditionals.
  3. Except if; used with hypothetical conditionals.
    • 1809, The Naval Chronicle for 1809: Containing a General and Biographical History of the Royal Navy of the United Kingdom with a Variety of Original Papers on Nautical Subjects. Vol. XXII. (from July to December), Cambridge University Press, 2010, page 482 (Google Books view):
      Q. If Lieutenant P. had given the word "Fire," would you have fired, and at what?—A. I should not have known, unless he had told me what to fire at.
    • 1847, Emily Brontë, Wuthering Heights, Chapter III
      Lie down and finish out the night, since you are here; but, for heaven's sake! don't repeat that horrid noise: nothing could excuse it, unless you were having your throat cut!
    • 1981, Arthur C. Danto, The Transfiguration of the Commonplace: A Philosophy of Art, page 118 (Google Books view):
      Suppose Breugel had done the whole painting with no legs. Then, titled as it is, it would be mystifying, unless someone were to say: the boy has fallen in the waters and they have closed over him, calm is restored, life goes on (as in The Israelites Crossing the Red Sea).


  • (except on a condition): if

Derived terms[edit]