The defense of duress can render a contract void or voidable. The victim of duress can cancel the contract, at his option.
What is duress?
Duress is defined as follows: a wrongful act or threat by one person that forces another individual carry out some act or refrain from acting, in a manner that said party would not have done voluntarily. Thus, because of duress, there is no true “meeting of minds of the parties” (required for the contract to exist) and, therefore, there is no legally enforceable contract.
Some examples include: blackmail, threats of physical force or violence, or threats to institute frivolous or bad faith legal proceedings for an abusive purpose. That said, the threat to commence lawful proceedings for a legitimate purpose are not duress, but this can become duress when there is a corrupt intent to coerce a transaction that is totally outside and not related to the subject of such proceedings and is grossly unjust to the party injured by the conduct.