11.1.12 Invalidity is a legal term that refers to a situation in which a contract, agreement, or law is considered to be legally ineffective or unenforceable. Invalidity can be classified into two categories: void and voidable. A void contract or agreement is one that is considered to be legally invalid from its inception, and therefore has no legal force or effect. A voidable contract or agreement, on the other hand, is one that is valid until declared invalid by a court of law. Invalidity can arise from a variety of situations, including fraud, mistake, duress, undue influence, lack of capacity, or illegality. Invalidity can also be caused by a party's failure to comply with the terms of the contract or agreement.