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

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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 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 In a 6-3 decision, the justices said this location information showing where a cellphone user has traveled is personal and private and subject to the protection of the 4th Amendment’s ban on unreasonable searches. — Los Angeles Times, 29 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

Their ideas about it were often steeped in stereotypes suggesting that Buddhists were irrational and childish in their thinking.

— Livia Gershon, JSTOR Daily, 7 July 2026
Scammers often use isolation tactics in phone calls to panic the listener and rush them into making irrational choices that often have financial costs.

— Ella Moore July 2, Miami Herald, 2 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

That difference suggests that the government sees this extension of patent rights as an illegitimate way for a company to exclude other companies from competing.

— Julie Dawson, The Conversation, 23 June 2026
Some fraudsters run an illegitimate DME company and get a doctor to prescribe the equipment.

— Janice Neumann, Chicago Tribune, 16 June 2026

Definition of illegitimate

Adjective

In 2004, a Senate Intelligence Committee report concluded the CIA had provided unfounded assessments of the threat posed by Iraq that the Bush administration had relied on to justify going to war.

— Chicago Tribune, Chicago Tribune, 9 July 2026
But executive fears about AI rollouts are not unfounded, both fan sentiment and recent missteps suggest the risk is real.

— Sam Birchall, Fortune, 9 July 2026

Definition of unfounded

Adjective

These charges were so baseless that the Cook County State’s Attorney declined to prosecute me and expunged my name and the charge from the record.

— Literary Hub, Literary Hub, 14 July 2026
State Senator Tony Strickland, who represents Huntington and Newport Beach, said those concerns were baseless.

— Haley Parsley, Sacbee.com, 9 July 2026

Definition of baseless

Adjective

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
But in addition to saying the city’s 650-foot rule was invalid, the state also included a threat.

— Teri Sforza, Oc Register, 9 July 2026

Definition of invalid

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unreason

unreasonable

unreasonableness

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“Unreasonable.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/unreasonable. Accessed 17 Jul. 2026.

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Synonyms of unreasonable

adjective

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