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.
As always, some people will argue that demanding more is unreasonable, that Palace are already punching above their weight. Matt Woosnam, New York Times, 19 Aug. 2025 There are ways to encourage tenants to be good neighbors without being unreasonable or punitive. Kelly G. Richardson, San Diego Union-Tribune, 19 Aug. 2025 Responses to the post were divided on whether the woman’s expectations for the dog to be removed during her daughter’s visits were unreasonable. Latoya Gayle, People.com, 16 Aug. 2025 The lawsuit accuses Aber and the others of violating the women’s constitutional rights, including their rights to privacy and to be protected against unreasonable searches. Colleen Slevin, Denver Post, 15 Aug. 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

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Cite this Entry

“Unreasonable.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unreasonable. Accessed 22 Aug. 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

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