UNREASONABLE Synonyms: 124 Similar and Opposite Words

unreasonable

adjective

ˌən-ˈrēz-nə-bəl

Definition of unreasonable

as in unwarranted

having no basis in reason or fact an unreasonable assumption

Synonyms & Similar Words

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Antonyms & Near Antonyms

as in irrational

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 Thompson asserted that the monitoring constituted unreasonable search and seizure, but a federal appeals court denied his claim last year. — ABC News, 14 Sep. 2026 This was a unit that hemorrhaged yards last season, relying on takeaways to an unreasonable extent. — Andy Behrens, New York Times, 14 Sep. 2026 These pull-on pants are on my radar for the days when leggings feel a little too casual but real trousers sound completely unreasonable. — Chaise Sanders, Travel + Leisure, 14 Sep. 2026 Believable people with reasonable reactions forced to cope with seemingly unbelievable and unreasonable situations. — Culture Critic, Los Angeles Times, 11 Sep. 2026 See All Example Sentences for unreasonable

Recent Examples of Synonyms for unreasonable

Adjective

Eritrean Information Minister Yemane Gebremeskel said the sanctions were unwarranted and caused considerable damage to his country.

— ABC News, ABC News, 19 Sep. 2026
Last year, the panel also made several unwarranted changes to vaccine recommendations, including dropping the universal recommendation for a birth dose of the hepatitis B vaccine—a move widely decried by medical and health experts.

— Beth Mole, ArsTechnica, 24 Aug. 2026

Definition of unwarranted

Adjective

The fact, in other words, that there often isn’t a right answer or a clear victor—and that rational people are subject to irrational forces within and above them.

— Max Norman, Harpers Magazine, 22 Sep. 2026
Mathematicians have long known that some polynomial equations have only rational solutions, while others have irrational solutions (such as ).

— Lyndie Chiou, Scientific American, 22 Sep. 2026

Definition of irrational

Adjective

The two got married in April, CBS reported, and Danis also became the subject of unfounded conspiracy theories alongside her new husband.

— Rebekah Riess, CNN Money, 21 Sep. 2026
Fox's attorneys noted that Rupert Murdoch had been auto-deleting all of his text messages until about April 2022, which was after Dominion had filed its lawsuit against Fox for broadcasting unfounded conspiracy theories about the 2020 election.

— Maddy Lauria, NPR, 20 Sep. 2026

Definition of unfounded

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

The researchers suspect that others were created by AI that either hallucinated or, just like the AI agents browsing their file, couldn’t distinguish between legitimate and illegitimate instructions.

— Dan Goodin, ArsTechnica, 27 Aug. 2026
Internet discussions portrayed the SPLC as a politically motivated or illegitimate actor.

— Art Jipson, The Conversation, 20 Aug. 2026

Definition of illegitimate

Adjective

In 2018, a university climate survey revealed Native students felt the most unsupported on campus, according to Reed.

— Emma Hall, Sacbee.com, 16 Sep. 2026
This reluctance is common and means many go unseen and unsupported, even when local organizations like Good Samaritan Outreach stand ready to help.

— Christine Franz, The Orlando Sentinel, 8 Sep. 2026

Definition of unsupported

Adjective

Social media in South Korea have been filled with messages stoking fears about safety on Jeju, with some spreading groundless rumors and deriding the island.

— Hyung-Jin Kim, Los Angeles Times, 27 Aug. 2026
For Rocha, however, the claims examined in the documentary are groundless — and tiring.

— Johnny Dodd, PEOPLE, 15 July 2026

Definition of groundless

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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 24 Sep. 2026.

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Synonyms of unreasonable

adjective

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