unreasonable

adjective

un·​rea·​son·​able
ˌən-ˈrēz-nə-bəl,
-ˈrē-zᵊn-ə-bəl How to pronounce unreasonable (audio)
1
a
: not governed by or acting according to reason
unreasonable people
b
: not conformable to reason : absurd
unreasonable beliefs
2
: exceeding the bounds of reason or moderation
working under unreasonable pressure
unreasonableness
ˌən-ˈrēz-nə-bəl-nəs
-ˈrē-zᵊn-ə-bəl- How to pronounce unreasonable (audio)
noun
unreasonably
ˌən-ˈrēz-nə-blē
-ˈrē-zᵊn-ə-blē How to pronounce unreasonable (audio)
adverb

Examples of unreasonable in a Sentence

I told him that I wouldn't pay unless he sent me a replacement. Am I being unreasonable? You are entitled to compensation for unreasonable delays.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The same could be true of the recent cost estimates, but construction technology has advanced in the past half century, so that lower costs per mile are not unreasonable. Michael Lynch, Forbes.com, 25 July 2025 Barbara Attard, a police accountability expert, said meet and confer can last months, but beyond a year is unreasonable. Kelly Davis, San Diego Union-Tribune, 25 July 2025 His exact demands are unknown but given his status as one of the world’s leading players a range of £250,000 to £300,000 a week is far from unreasonable. Chris Weatherspoon, New York Times, 25 July 2025 Public nuisance: OpenAI’s deployment of increasingly capable AI systems without adequate safety measures creates an unreasonable interference with public rights in Hawaii. Tamlyn Hunt, Scientific American, 22 July 2025 See All Example Sentences for unreasonable

Word History

First Known Use

14th century, in the meaning defined at sense 1a

Time Traveler
The first known use of unreasonable was in the 14th century

Browse Nearby Words

Cite this Entry

“Unreasonable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unreasonable. Accessed 29 Jul. 2025.

Legal Definition

unreasonable

adjective
un·​rea·​son·​able
: not reasonable : beyond what can be accepted: as
a
: clearly inappropriate, excessive, or harmful in degree or kind
an unreasonable delay
an unreasonable restraint of trade
b
: lacking justification in fact or circumstance
an unreasonable inference
especially : irrational sense b
the agency decision was unreasonable
c
: not supported by a warrant or by a valid exception to a warrant requirement (as when there is reasonable suspicion) and therefore unconstitutional
the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violatedU.S. Constitution amend. IV
see also search, seizure
unreasonableness noun
unreasonably adverb

More from Merriam-Webster on unreasonable

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!