Indian Contract Act, 1872

A contract is an agreement enforceable by law: an offer accepted, with lawful consideration and lawful object, by parties competent to contract, with free consent. Worked example: A offers to sell a cycle for ₹5,000, B accepts, and both are adults of sound mind — that is a contract. If B accepted only because A threatened him, consent is not free and the contract is voidable at B's option, not automatically void.