[uhn-ree-zuh n]
See more synonyms for unreason on Thesaurus.com
  1. inability or unwillingness to think or act rationally, reasonably, or sensibly; irrationality.
  2. lack of reason or sanity; madness; confusion; disorder; chaos: a world torn by unreason.
verb (used with object)
  1. to upset or disrupt the reason or sanity of: The devious plot soon unreasoned the general.

Origin of unreason

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


[ree-zuh nd]
  1. based on reason: a carefully reasoned decision.
  2. 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. 2018

Examples from the Web for unreasoned

Historical Examples of unreasoned

British Dictionary definitions for unreasoned


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


  1. irrationality or madness
  2. something that lacks or is contrary to reason
  3. lack of order; chaos
  1. (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