An agreement not enforceable by law is said to be void.
The following types of agreements are considered to be void:
i) Agreements where consideration and objects are unlawful in part
If any part of a single consideration for one or more objects, or any one or any part of any one of several considerations for a single object, is unlawful, the agreement is void.
ii) Agreements without consideration
It is a well settled proposition of the law of contract that an agreement without consideration is void.
iii) Agreements in restraint of marriage
Every agreement in restraint of the marriage of any person, other than a minor is void.
iv) Agreements in restraint of trade
Every agreement by which any one is restrained from exercising a lawful profession, trade or business of any kind, is to that extent is void.
v) Agreements in restraint of legal proceedings
Every agreement by which any party thereto is restricted absolutely from enforcing his rights under or in respect of any contract, by the usual legal proceedings in the ordinary tribunals, or which limits the time within which he may thus enforce his rights, is void to that extent.
vi) Uncertain Agreements
Agreements, the meaning of which is not certain, or capable of being made certain, are void.
vii) Agreements of wager
A wager is an agreement by which money is payable by one person to another on the happening or non- happening of a future, uncertain event. These agreements are considered to be void in nature.
viii) Impossible acts
An agreement which requires performing an act which is impossible in itself is void.
An agreement which can be avoided is known as a voidable agreement. An agreement which is enforceable by law at the option of one or more of the parties thereto, but not at the option of the other or others, is a voidable contract.
All contracts under the influence of coercion, undue influence or misrepresentation are examples of voidable contracts.