Void vs Voidable Contract

A void contract has no legal effect and was never enforceable, such as an agreement for an illegal purpose. A voidable contract is valid and enforceable until the protected party elects to void, or disaffirm, it.

A minor's contract is the classic voidable contract: the minor may enforce it or disaffirm it. An unenforceable contract is a third category, valid in form but not enforceable in court, such as an oral land sale under the Statute of Frauds.

Capacity is where the two split, and not every incapacity lands on the same side. A minor, or an adult of unsound mind whom no court has adjudicated, produces a voidable contract, because the law is protecting that party and gives them the choice. A person a court has already adjudicated incompetent produces a void contract, because the authority to contract has passed to a guardian and there is none left to exercise.