[uhn-ree-zuh-nuh-buhl, -reez-nuh-]


not reasonable or rational; acting at variance with or contrary to reason; not guided by reason or sound judgment; irrational: an unreasonable person.
not in accordance with practical realities, as attitude or behavior; inappropriate: His Bohemianism was an unreasonable way of life for one so rich.
excessive, immoderate, or exorbitant; unconscionable: an unreasonable price; unreasonable demands.
not having the faculty of reason.

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

Synonyms for unreasonable

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

Examples from the Web for unreasonableness

Historical Examples of unreasonableness

  • But the unreasonableness of such a suspicion was patent, and Mr Verloc held his tongue.

    The Secret Agent

    Joseph Conrad

  • What I had done I had done as much to win Roxalanne to me as to win her from her own unreasonableness.

  • It was Tom who pointed out the unreasonableness of emotion in making this demand.

  • Her wishes had none of the unreasonableness of dying fancies.

    Rene Mauperin

    Edmond de Goncourt and Jules de Goncourt

  • Thus he sat wondering, dismayed by the unreasonableness of women.

    The Dark Flower

    John Galsworthy

British Dictionary definitions for unreasonableness



immoderate; excessiveunreasonable demands
refusing to listen to reason
lacking reason or judgment
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 unreasonableness



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

Online Etymology Dictionary, © 2010 Douglas Harper