unreasonable
Americanadjective
-
not reasonable or rational; acting at variance with or contrary to reason; not guided by reason or sound judgment; irrational.
an unreasonable person.
-
not in accordance with practical realities, as attitude or behavior; inappropriate.
His Bohemianism was an unreasonable way of life for one so rich.
- Synonyms:
- nonsensical, stupid, absurd, preposterous, silly, foolish, senseless
-
excessive, immoderate, or exorbitant; unconscionable.
an unreasonable price; unreasonable demands.
- Synonyms:
- extravagant
-
not having the faculty of reason.
adjective
-
immoderate; excessive
unreasonable demands
-
refusing to listen to reason
-
lacking reason or judgment
Other Word Forms
Etymology
Origin of unreasonable
First recorded in 1300–50, unreasonable is from the Middle English word unresonabel. See un- 1, reasonable
Explanation
To be unreasonable means acting in an irrational way. Your expectation that your favorite team will win the Super Bowl every year is unreasonable. When someone's unreasonable, they're not using reason, or common sense, to make decisions or demands. Add the prefix un- to reasonable, "having sound judgment," and you get an adjective that's perfect for describing illogical behavior. It's often used for a certain kind of demanding stubbornness too: "It's completely unreasonable to make your server take your soup back five times to warm it up a little more."
Vocabulary lists containing unreasonable
"The Southpaw"
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Chronically Dolores
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Part 3 Vocabulary (Unit 2)
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
What happened: Iranian Foreign Ministry spokesperson Esmail Baghaei once again rejected that direct talks with the U.S. had taken place, describing the proposed terms as “unrealistic, unreasonable and excessive.”
From Los Angeles Times ● Aug. 28, 2026
Baldoni’s lawyer, Bryan Freedman, said the court agreed with his argument that Lively’s claim for $8 million was unreasonable.
From The Wall Street Journal ● Aug. 26, 2026
The judge has ruled that the group presented their claims in a way that was "unreasonable to a high degree".
From BBC ● Aug. 22, 2026
“If the agreement defines a direct competitor as any other company under the sun, that could be considered unreasonable and then that agreement could not be enforceable,” he says.
From MarketWatch ● Aug. 21, 2026
Of course he knew how unreasonable the American embassy could be—the vice chancellor, of all people, had once been refused a visa to attend a conference—but he had never doubted his plan.
From "Americanah" by Chimamanda Ngozi Adichie
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
