Which aspect of a contract must be lawful for the contract to be enforceable?

For a contract to be enforceable, one crucial aspect is the subject matter of the contract. The subject matter must be lawful; otherwise, the contract is void. This means that if a contract involves illegal activities or objectives, courts will not uphold it, as they cannot enforce agreements that are inherently unlawful.

This principle is grounded in public policy, which aims to prevent the enforcement of contracts that could harm individuals or society. For example, a contract for the sale of illegal drugs or any agreement that requires one party to engage in fraudulent activities would be considered unenforceable due to the illegality of the subject matter.

Understanding this aspect is essential in contract law, as it underpins the foundation upon which enforceable agreements are built. The other aspects mentioned, such as formality, validity, and severability, play roles in contract effectiveness and enforceability but do not directly address the legality of the contract's subject matter, which is paramount for enforceability.