Estoppel

Estoppel is a legal doctrine at common law, where a party is barred from claiming or denying an argument on an equitable ground. Estoppel complements the requirement of consideration in contract law. In general, estoppel protects an aggrieved party, if the counter-party induced an expectation from the aggrieved party, and the aggrieved party reasonably relied on that expectation and would suffer detriment if the expectation is not met.

While there are many types of estoppel, in simpler terms, most estoppels prohibit an individual or group from being harmed as a result of another's deeds, statements or promises, when later actions or statements contradict or undermine what was originally stated, promised, or inferred.

In litigation, estoppel is a defense and provides immunity to the defendant, by preventing the claimant or accuser from presenting statements of facts when such statements contradict earlier statements or when the party, by negligence, failed to present them earlier.

Additionally, estoppel as a defense may also provide a legal basis for a claim, when proof exists that the undermined actions or false promises, or the negligence to present the facts, caused harm to the defendant. In limited cases where statements or promises were not made explicitly, a party's silence alone may alone prevent them from making a later claim or statement.