UNREASONABLE Synonyms: 124 Similar and Opposite Words

unreasonable

adjective

ˌən-ˈrēz-nə-bəl

Definition of unreasonable

as in irrational

having no basis in reason or fact an unreasonable assumption

Synonyms & Similar Words

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Antonyms & Near Antonyms

as in unreasoning

not using or following good reasoning an unreasonable respect for a man who did not deserve it

Synonyms & Similar Words

Antonyms & Near Antonyms

Example Sentences

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.

Recent Examples of unreasonable Your request for back-to-back weeks off at the last minute is unreasonable. — Harriette Cole, Mercury News, 3 July 2026 If these requirements are not met, the search is unreasonable and therefore unlawful, and evidence obtained in that search cannot be used in court, barring a good-faith exception. — Anne Toomey McKenna, The Conversation, 30 June 2026 Justices ruled that sweeping use of cellphone data requires a warrant, a decision applying the Fourth Amendment, which protects against unreasonable searches and seizures, to new technology. — Josh Feldman, NBC news, 30 June 2026 Instead, writing for the majority, Justice Elena Kagan said concluding that a Fourth Amendment search occurred doesn't resolve whether the warrant was lawful, because the Fourth Amendment only prohibits unreasonable searches. — Maureen Groppe, USA Today, 29 June 2026 See All Example Sentences for unreasonable

Recent Examples of Synonyms for unreasonable

Adjective

In both cases, cheap credit fueled the irrational exuberance.

— Annie Lowrey, The Atlantic, 21 July 2026
An irrational holding on to the possibility of a comeback, if that was the word if no one noticed you’d retired in the first place.

— Literary Hub, Literary Hub, 17 July 2026

Definition of irrational

Adjective

But in each event—in the living act, the undoubted deed—there, some unknown but still reasoning thing puts forth the mouldings of its features from behind the unreasoning mask.

— Literary Hub, Literary Hub, 6 July 2026
Roosevelt surely understood that nameless, unreasoning, unjustified fear cannot be eradicated.

— New York Times, New York Times, 9 June 2026

Definition of unreasoning

Adjective

His 64th-minute foul, which the Americans believed was unwarranted and accidental, put the host nation in a precarious position despite being heavy favorites to move on to the Round of 16.

— Chris Biderman, Sacbee.com, 2 July 2026
None of which is an unwarranted attack on trucking as a mode of shipment.

— John Tamny, Forbes.com, 29 June 2026

Definition of unwarranted

Adjective

But that’s forcing them to wrestle with the idea that any action taken by a party is illegitimate, anti-democratic rigging — something the other team can use to depress the base.

— David Weigel, semafor.com, 22 July 2026
Signature-matching efforts sometimes disqualify more legitimate than illegitimate ballots.

— Jeremy Kohler, ProPublica, 15 July 2026

Definition of illegitimate

Adjective

Historically, fears surrounding novels, radio, and television proved largely unfounded, though each gradually reshaped human habits.

— Michael Edmondson, Forbes.com, 21 July 2026
Tincon last spring said the concerns were unfounded and described itself as a responsible corporate neighbor, but ended up withdrawing its application before a vote.

— Don Stacom, Hartford Courant, 18 July 2026

Definition of unfounded

Adjective

Trump’s narrow loss in Arizona in 2020 and his subsequent — and baseless — insistence that fraud accounted for the defeat has fueled an election denialism that Arizona voters have rarely rewarded.

— Arizona Republic, AZCentral.com, 21 July 2026
In an address from the White House tonight, the president sought to reveal proof for his baseless assertions of a 2020 vote marred by fraud.

— Michael Scherer, The Atlantic, 17 July 2026

Definition of baseless

Adjective

Ashley accused Doug of psychologically abusing her, but prosecutors argued the allegations were unsupported by the evidence.

— Stephanie Nolasco, FOXNews.com, 25 July 2026
Procurement rewards the cheapest compliant bid, so the unpatched, unsupported systems everyone worries about are exactly what the buying process keeps choosing.

— Expert Panel®, Forbes.com, 23 July 2026

Definition of unsupported

Adjective

Costco is not liable for incentives not received due to entry of an invalid address during sign-up.

— New Atlas, New Atlas, 23 July 2026
He was barred from the ballot paper after Russia’s Supreme Court ruled that more than 9,000 signatures submitted by Nadezhdin’s campaign were invalid — enough to disqualify him.

— ABC News, ABC News, 13 July 2026

Definition of invalid

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unreason

unreasonable

unreasonableness

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Style

“Unreasonable.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unreasonable. Accessed 29 Jul. 2026.

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Synonyms of unreasonable

adjective

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