warn
Americanverb (used with object)
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to give notice, advice, or intimation to (a person, group, etc.) of danger, impending evil, possible harm, or anything else unfavorable.
They warned him of a plot against him. She was warned that her life was in danger.
- Synonyms:
- forewarn
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to urge or advise to be careful; caution.
to warn a careless driver.
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to admonish or exhort, as to action or conduct.
She warned her employees to be on time.
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to notify, advise, or inform.
to warn a person of an intended visit.
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to give notice to (a person, group, etc.) to go, keep at a distance, etc. (often followed by away, off, etc.).
A sign warns trespassers off the grounds. A marker warned boats away from the dock.
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to give authoritative or formal notice to (someone); order; summon.
to warn a person to appear in court.
verb (used without object)
verb
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to notify or make (someone) aware of danger, harm, etc
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(tr; often takes a negative and an infinitive) to advise or admonish (someone) as to action, conduct, etc
I warn you not to do that again
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(takes a clause as object or an infinitive) to inform (someone) in advance
he warned them that he would arrive late
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(tr; usually foll by away, off, etc) to give notice to go away, be off, etc
he warned the trespassers off his ground
Related Words
Warn, caution, admonish imply attempting to prevent another from running into danger or getting into unpleasant or undesirable circumstances. To warn is to speak plainly and usually in strong terms: to warn him about danger and possible penalties. To caution is to advise about necessary precautions, to put one on one's guard about possibly harmful circumstances or conditions, thus emphasizing avoidance of undesirable consequences: to caution him against driving in such weather. Admonish suggests giving earnest, authoritative advice with only tacit references to danger or penalty: to admonish a person for neglecting his duties.
Other Word Forms
- prewarn verb (used with object)
- rewarn verb (used with object)
- unwarned adjective
- warner noun
- well-warned adjective
Etymology
Origin of warn
First recorded before 1000; Middle English warnen, Old English warnian; cognate with German warnen; ware 2
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.
While much of 2025 was a victory lap for crypto, some analysts now warn that a bear market has taken hold and is here to stay.
Famed investor Michael Burry in November started Cassandra Unchained on Substack, where he shares his investment theories, including a recent one warning about an AI bubble.
Authorities, however, have also promised to take a "firm" stance, and have warned against exploiting the situation to sow chaos.
From Barron's
But he warned their relationship could quickly sour.
From Barron's
When the nights of feeding still drag and the days creep along like a slug, people will warn you with a knowing air that your baby’s life will “go so fast.”
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.
