Mandamus: (Latin: we command) High Court order commanding an individual, organisation, administrative tribunal or court to perform a certain action – usually to correct an earlier illegal action or failure to fulfil some statutory duty.

Mediation: Form of alternative dispute resolution involving an agreed mediator acting as a facilitator to help the parties negotiate an agreement. The mediator does not adjudicate on the issues or force a compromise only the parties involved can resolve the dispute. The result of a successful mediation is called a settlement.

Mens rea: (Latin: guilty mind) Most crimes require proof of guilty intention before a person can be convicted. The prosecution must prove either that the accused knew his action was illegal or that he was reckless or grossly negligent. Some offences (such as drunken driving) are matters of strict liability, which means that the intention or state of mind of the person committing the offence is irrelevant.

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.