unreasonable

adjective

un·​rea·​son·​able

ˌən-ˈrēz-nə-bəl,

-ˈrē-zᵊn-ə-bəl 

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- 

noun

unreasonably

ˌən-ˈrēz-nə-blē

-ˈrē-zᵊn-ə-blē 

adverb

Synonyms

• baseless
• foundationless
• groundless
• invalid
• nonvalid
• unfounded
• unsubstantiated
• unsupported
• unwarranted

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

This piece of jewelry is meant to be special, but not unreasonable. —Gia Yetikyel, Vogue, 3 Dec. 2024

Only Carragher and Salah's other critics can explain why De Bruyne is exempt from the same, if unreasonable, critique. —Zak Garner-Purkis, Forbes, 28 Nov. 2024

The Justice Department concluded that the Trenton Police Department's practices violated Fourth Amendment protections against unreasonable searches and seizures. —Matthew Impelli, Newsweek, 21 Nov. 2024

Demanding everyone unilaterally go back to the office post-COVID-19 is an expensive and unreasonable request for far too many. —Michele Weldon, Chicago Tribune, 18 Nov. 2024

Word History

First Known Use

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

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 violated

—U.S. Constitution amend. IV

see also search, seizure

unreasonableness noun

unreasonably adverb