not predictable; not to be foreseen or foretold: an unpredictable occurrence.


something that is unpredictable: the unpredictables of life.

Origin of unpredictable

First recorded in 1855–60; un-1 + predictable
Related formsun·pre·dict·a·bil·i·ty, un·pre·dict·a·ble·ness, nounun·pre·dict·a·bly, adverb

Synonyms for unpredictable

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for unpredictable

Contemporary Examples of unpredictable

Historical Examples of unpredictable

  • Often its leaps and flickerings are irregular, inconsistent, unpredictable.

    Cleo The Magnificent

    Louis Zangwill

  • In E science the unpredictable, the incredible, the illogical could happen at any time.

    Eight Keys to Eden

    Mark Irvin Clifton

  • The planet, though, was of no use to humanity because it was unpredictable.

    Talents, Incorporated

    William Fitzgerald Jenkins

  • Some changes are unpredictable, even in deterministic principle.

    After the Rain

    Sam Vaknin

  • It is that which is by its nature irregular and unpredictable.


    George Grote

British Dictionary definitions for unpredictable



not capable of being predicted; changeable
Derived Formsunpredictability or unpredictableness, noununpredictably, adverb
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 unpredictable

1857, from un- (1) "not" + predictable. Related: Unpredictably; unpredictability.

Online Etymology Dictionary, © 2010 Douglas Harper