Minor: Person under the age of 18 who is not married (or has not been married). A minor may only enter into certain contracts, such as those for necessaries or an apprenticeship. A Irish resident under the age of 18 may not legally marry, even if the ceremony takes place in a place (such as Northern Ireland) where the minimum age for marriage is under 18.

Misfeasance: Improperly doing something which a person has a legal right to do. Contrast with nonfeasance.

Misjoinder: When a person has been wrongly named as a party to a law suit, a court will usually amend the proceedings to strike out the name of the misjoined party and substitute the person who should have been joined.

Misrepresentation: False material statement which induces a party to enter into a contract grounds for rescission of the contract.

Mitigation: Facts which, while not negating an offence or wrongful action, tend to show that the defendant may have had some excuse for acting the way he did. For example, provocation may constitute mitigating circumstances in an assault action.

Mitigation of damages: A person who sues another for damages has a duty to minimize his loss, as far as reasonable. For example, in a wrongful dismissal suit, the person who was fired should make some effort to find another job, to minimize the economic damage to himself.

Moiety: Half of anything. For example, joint tenants each hold a moiety of the property.

Mortgage: An interest given on land, in writing, to guarantee the payment of a debt or the execution of some action. It automatically becomes void when the debt is paid or the action is executed. The person lending the money and receiving the mortgage is called the mortgagee the person who concedes a mortgage as security upon his property is called a mortgagor. The three types of mortgage are a legal mortgage (involving a transfer of the legal interest in the property), an equitable mortgage (by depositing the title deeds) and a judgment mortgage (following a court judgment).

Natural justice: The requirement for application of the tenets audi alteram partem (hear the other side) and nemo judex in causa sua (no-one may be a judge in his own case). The principles of natural justice were derived from the Romans, who believed that some legal principles were natural or self-evident and did not need a statutory basis.

Natural person: Human being with legal and Constitutional rights and duties, including the right to life, right to information, right to travel, right to a good name, right to earn a living, right to sue and be sued, to sign contracts, to receive gifts and to appear in court either by himself or through a lawyer. Individuals are persons in law unless they are minors or under some other type of incapacity, such as a court finding of mental incapacity. Contrast with a company, which is a legal person.