[uhn-les, uh n-]
See more synonyms for unless on Thesaurus.com
  1. except; but; save: Nothing will come of it, unless disaster.

Origin of unless

1400–50; late ME prepositional phrase on less (also o less(e), earlier upon less) on a lesser footing or condition (than); first used as a preposition and conjunction in the early 16th century; see on, less
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for unless

but, except, saving, without, lest, nisi

Examples from the Web for unless

Contemporary Examples of unless

Historical Examples of unless

  • "Unless it should be his gracious pleasure to dispense with obedience," replied Artaphernes.


    Lydia Maria Child

  • But unless he did something a hundred lives perhaps might be lost.

    Brave and Bold

    Horatio Alger

  • Unless you do as I bid you, I will keep you in irons for the rest of the voyage!

    Brave and Bold

    Horatio Alger

  • "That'll be enough for us, unless you are very hungry," said Robert.

    Brave and Bold

    Horatio Alger

  • Unless we are fortunate enough to find some, retreat is inevitable.

British Dictionary definitions for unless


  1. (subordinating) except under the circumstances that; except on the condition thatthey'll sell it unless he hears otherwise
  1. rare except

Word Origin for unless

C14: onlesse, from on on + lesse less; compare French à moins que, literally: at less than
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for unless

mid-15c., earlier onlesse, from on lesse (than) "on a less condition (than)," the first syllable originally on, but the negative connotation and the lack of stress changed it to un-.

Online Etymology Dictionary, © 2010 Douglas Harper