A void contract is an agreement that is not legally enforceable from the moment it is created. This means that, even if both parties agree to the terms, the contract has no legal effect. Common reasons for a contract to be void include illegality, lack of capacity, or if it involves impossible actions. For example, if a contract involves the sale of illegal drugs, it is void because the subject matter is illegal. Similarly, if one party is a minor or mentally incapacitated, the contract may also be void due to lack of capacity.