reasonable

[ree-zuh-nuh-buhl, reez-nuh-]
adjective
  1. agreeable to reason or sound judgment; logical: a reasonable choice for chairman.
  2. not exceeding the limit prescribed by reason; not excessive: reasonable terms.
  3. moderate, especially in price; not expensive: The coat was reasonable but not cheap.
  4. endowed with reason.
  5. capable of rational behavior, decision, etc.

Origin of reasonable

1250–1300; Middle English resonable < Middle French raisonnable < Latin ratiōnābilis. See reason, -able
Related formsrea·son·a·ble·ness, rea·son·a·bil·i·ty, nounrea·son·a·bly, adverbhalf-rea·son·a·ble, adjectivehalf-rea·son·a·bly, adverbnon·rea·son·a·bil·i·ty, nounnon·rea·son·a·ble, adjectivenon·rea·son·a·ble·ness, nounnon·rea·son·a·bly, adverbqua·si-rea·son·a·ble, adjectivequa·si-rea·son·a·bly, adverb
Can be confusedrational reasonable (see synonym study at the current entry)

Synonyms for reasonable

1. intelligent, judicious, wise, equitable. Reasonable, rational refer to the faculty of reasoning. Rational can refer to the reasoning faculty itself or to something derived from that faculty: rational powers; a rational analysis. It can also mean sane or sensible: She was no longer rational; a rational plan. Reasonable most often means sensible: A reasonable supposition is one which appeals to our common sense. 2. equitable, fair, just. See moderate.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for reasonability

reasonable

adjective
  1. showing reason or sound judgment
  2. having the ability to reason
  3. having modest or moderate expectations; not making unfair demands
  4. moderate in price; not expensive
  5. fair; averagereasonable weather
Derived Formsreasonably, adverbreasonableness, noun
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 reasonability

reasonable

adj.

c.1300, "having sound judgment, sane, rational," from Old French raisonable, from Latin rationabilis, from ratio (see reason (n.)).

What the majority of people consider to be 'reasonable' is that about which there is agreement, if not among all, at least among a substantial number of people; 'reasonable' for most people, has nothing to do with reason, but with consensus. [Erich Fromm, "The Heart of Man," 1968]

Meaning "moderate in price" is recorded from 1660s. Related: Reasonably.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with reasonability

reasonable

see beyond a (reasonable) doubt.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.