Free Consent

Section 13 defines consent: two or more persons are said to consent when they agree upon the same thing in the same sense (called "consensus ad idem"). Section 14 further requires that consent be free — that is, not caused by any of the following five factors. If consent is not free, the contract is voidable at the option of the party whose consent was so caused (except in the case of mistake, which can make an agreement void).

• Coercion (Section 15) — committing or threatening to commit any act forbidden by the Indian Penal Code, or unlawfully detaining or threatening to detain property, to compel a person to enter into an agreement.
• Undue influence (Section 16) — where one party is in a position to dominate the will of the other (e.g. a real/apparent authority over the other, a fiduciary relationship, or a contract with a person whose mental capacity is temporarily/permanently affected) and uses that position to obtain an unfair advantage.
• Fraud (Section 17) — a false representation of a fact, made knowingly, without belief in its truth, or recklessly, with the intent to deceive the other party and induce them to enter the contract; it includes active concealment of a fact by a party who has a duty to disclose it.
• Misrepresentation (Section 18) — an innocent, unintentional false statement of fact, made by a person honestly believing it to be true, which nonetheless induces the other party to enter the contract.
• Mistake (Sections 20–22) — an erroneous belief about a matter of fact or law. A bilateral mistake by both parties about an essential fact makes the agreement void; a unilateral mistake by only one party generally does not affect the validity of a contract. …