estoppel

American  

[e-stop-uhl] / ɛˈstɒp əl /

noun

Law.

1. a bar or impediment preventing a party from asserting a fact or a claim inconsistent with a position that party previously took, either by conduct or words, especially where a representation has been relied or acted upon by others.

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estoppel British  

/ ɪˈstɒpəl /

noun

1. law a rule of evidence whereby a person is precluded from denying the truth of a statement of facts he has previously asserted See also conclusion

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Etymology

Origin of estoppel

First recorded in 1575–85, estoppel is from the Middle French word estoupail stopper. See estop, -al ²

Explanation

Estoppel is a legal rule that bars people from making statements that contradict something they've already said or done. By using estoppel, a court can hold someone to their word. Estoppel comes from estop, "to bar or stop" in legal language, which is from a root meaning "to stop or plug up." The purpose of estoppel is to keep one person from being harmed by another's inconsistencies or contradictions. This legal tool might be used if a landlord suddenly changes the terms of a contract he's previously agreed to. Estoppel is also used to keep people from contradicting something that's already legally proven to be true.

Example Sentences

That email is what starts the clock on estoppel.

From MarketWatch • Feb. 23, 2026

Judicial estoppel, the doctrine preventing parties from abandoning positions they successfully argued before, may offer importers some protection.

From The Wall Street Journal • Feb. 22, 2026

But thanks to collateral estoppel, the government may not get hundreds of chances to win.

From Salon • Jun. 30, 2025

That became the basis for their defense, known as entrapment by estoppel, in which a defendant essentially argues that he broke the law based on bad advice from a government official.

From Los Angeles Times • Jan. 31, 2024

Waiver by a surety of the defense of release by giving time to the principal needs no element of consideration nor of estoppel.

From An Introduction to the Philosophy of Law by Pound, Roscoe