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[uhn-ri-lahy-uh-buh l] /ˌʌn rɪˈlaɪ ə bəl/
not reliable; not to be relied or depended on.
Origin of unreliable
1830-40; un-1 + reliable
Related forms
unreliability, unreliableness, noun
unreliably, adverb
undependable, irresponsible, untrustworthy. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for unreliability
Contemporary Examples
Historical Examples
  • Elsewhere has been mentioned the confusion prevailing in those extracts, and their unreliability as historical evidences.

    The Life of Cesare Borgia Raphael Sabatini
  • Who has not heard the lament about the unreliability of the senses?

  • They were a warlike offshoot of the Hoonahs, and bore a bad reputation for treachery and unreliability.

    Alaska Ella Higginson
  • All this was done to show the unreliability of circumstantial evidence.

    The Crime of the Century Henry M. Hunt
  • It was not the chief cause of disorder, however, for that was the unreliability of the regimental officers.

  • These gave the horse the reputation of capriciousness and unreliability.

    Clever Hans Oskar Pfungst
  • The unreliability of rules is further explained by their rise from generalization.

    Criminal Psychology Hans Gross
  • The resulting value for r was -24, with an unreliability of 186.

    Adenoids and Diseased Tonsils Margaret Cobb Rogers
British Dictionary definitions for unreliability


not reliable; untrustworthy: an unreliable witness
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 unreliability



1840, from un- (1) "not" + reliable. First recorded in De Quincey, who said it was coined by Coleridge.

Online Etymology Dictionary, © 2010 Douglas Harper
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