• synonyms


[uhn-ree-zuh-nuh-buh l, -reez-nuh-]
See more synonyms for unreasonable on Thesaurus.com
  1. not reasonable or rational; acting at variance with or contrary to reason; not guided by reason or sound judgment; irrational: an unreasonable person.
  2. not in accordance with practical realities, as attitude or behavior; inappropriate: His Bohemianism was an unreasonable way of life for one so rich.
  3. excessive, immoderate, or exorbitant; unconscionable: an unreasonable price; unreasonable demands.
  4. not having the faculty of reason.
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Origin of unreasonable

First recorded in 1300–50, unreasonable is from the Middle English word unresonabel. See un-1, reasonable
Related formsun·rea·son·a·ble·ness, nounun·rea·son·a·bly, adverb


See more synonyms for unreasonable on Thesaurus.com
1, 2. senseless, foolish, silly. 2. preposterous, absurd, stupid, nonsensical. 3. extravagant.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for unreasonably

Contemporary Examples

Historical Examples

  • This act of justice has been unreasonably delayed in the case of some of them.

  • That local rates are unreasonably high, as compared with through rates.

    The Railroad Question

    William Larrabee

  • On the third day she had felt almost angry with him unreasonably.

    A Spirit in Prison

    Robert Hichens

  • Poor Jed, miserable and most unreasonably conscience-stricken, writhed in his chair.


    Joseph C. Lincoln

  • Instead his opposition was just as violent and, to his son's mind, as unreasonably absurd.


    Joseph C. Lincoln

British Dictionary definitions for unreasonably


  1. immoderate; excessiveunreasonable demands
  2. refusing to listen to reason
  3. lacking reason or judgment
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Derived Formsunreasonableness, noununreasonably, 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 unreasonably



mid-14c., from un- (1) "not" + reasonable. Related: Unreasonably.

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Online Etymology Dictionary, © 2010 Douglas Harper