term:

Duress

duress n

[Anglo-French duresce, literally, hardness, harshness, from Old French, from Latin duritia, from durus hard]
: wrongful and usually unlawful compulsion (as threats of physical violence) that induces a person to act against his or her will
: coercion
;also
: the affirmative defense of having acted under duress see also economic duress compare necessity, undue influence NOTE: A person may be able to avoid the consequences of his or her acts under the law if they were performed while under duress. For example, a contract made under duress is voidable by the coerced party. Similarly, a will signed under duress is invalid. Duress may also be used to justify a criminal act. A threat to bring a lawsuit is not duress.

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.