[ uhn-ree-zuh-nuh-buhl, -reez-nuh- ]
/ ʌnˈri zə nə bəl, -ˈriz nə- /


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

OTHER WORDS FROM unreasonable

un·rea·son·a·ble·ness, nounun·rea·son·a·bly, adverb
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for unreasonable

British Dictionary definitions for unreasonable

/ (ʌnˈriːznəbəl) /


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

Derived forms of unreasonable

unreasonableness, 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