[ uhn-ree-zuh n ]
/ ʌnˈri zən /


inability or unwillingness to think or act rationally, reasonably, or sensibly; irrationality.
lack of reason or sanity; madness; confusion; disorder; chaos: a world torn by unreason.

verb (used with object)

to upset or disrupt the reason or sanity of: The devious plot soon unreasoned the general.

Nearby words

  1. unrealistic,
  2. unreality,
  3. unrealizable,
  4. unrealized,
  5. unreally,
  6. unreasonable,
  7. unreasonable behaviour,
  8. unreasoning,
  9. unreckonable,
  10. unrecognizable

Origin of unreason

First recorded in 1250–1300, unreason is from the Middle English word un-reson. See un-1, reason


[ ree-zuh nd ]
/ ˈri zənd /


based on reason: a carefully reasoned decision.
containing reasons: a long, reasoned reply.

Origin of reasoned

First recorded in 1675–85; reason + -ed2

Related formsrea·soned·ly, adverbun·rea·soned, adjectivewell-rea·soned, adjective

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

Examples from the Web for unreasoned

British Dictionary definitions for unreasoned


/ (ˈriːzənd) /


well thought-out or well presenteda reasoned explanation
Derived Formsreasonedly, adverb


/ (ʌnˈriːzən) /


irrationality or madness
something that lacks or is contrary to reason
lack of order; chaos


(tr) to deprive of reason
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