unreason

[ uhn-ree-zuh n ]
/ ʌnˈri zən /

noun

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.

Origin of unreason

First recorded in 1250–1300, unreason is from the Middle English word un-reson. See un-1, reason
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for unreason

British Dictionary definitions for unreason

unreason
/ (ʌnˈriːzən) /

noun

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

verb

(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