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[uhn-bi-lee-vuh-buh l] /ˌʌn bɪˈli və bəl/
too dubious or improbable to be believed:
an unbelievable excuse.
so remarkable as to strain credulity; extraordinary:
the unbelievable fury of the storm; an unbelievable athlete.
Origin of unbelievable
1540-50; un-1 + believable
Related forms
unbelievably, adverb Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for unbelievable
Contemporary Examples
Historical Examples
  • What a strange night it had been for Hester—more like some unbelievable romance!

    Weighed and Wanting George MacDonald
  • Out of her presence what I had seen was unthinkable, unbelievable.

    The Bacillus of Beauty Harriet Stark
  • If Danny was right he had no words to fit the unbelievable truth.

    The Hammer of Thor Charles Willard Diffin
  • The idea that she should even think of marrying a play-actor was unbelievable.

    The Portygee Joseph Crosby Lincoln
  • Outside the south windows he witnessed an unbelievable thing.

    Lords of the Stratosphere Arthur J. Burks
British Dictionary definitions for unbelievable


unable to be believed; incredible or astonishing
Derived Forms
unbelievability, unbelievableness, noun
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
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Word Origin and History for unbelievable

1540s, from un- (1) "not" + believable. Related: Unbelievably.

Online Etymology Dictionary, © 2010 Douglas Harper
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