Negligence: Carelessness. A person who owes a duty of care to someone else and breaches it by lack of reasonable care may be liable in damages for negligence. The negligence may involve a positive deed or a failure to act. If no damage results, there can be no action. The standard of care required is usually that of the reasonable man, but a person who claims to have special skills (such as a surgeon) owes a higher duty of care.

Nemo judex in sua causa: (Latin: nobody may be a judge in his own case) Principle of natural justice. A judge must be seen to be free of bias and may not have any interest – personal, pecuniary or otherwise – in a case he is deciding. Also referred to as nemo debet esse judex in propria causa.

Next of kin: Person”s nearest blood relation. The expression has come to describe those persons most closely related to a dead person and therefore due to inherit his property if there is no will.

Non est factum: (Latin: not his deed) Defence in contract law which allows a person to avoid liability because he was mistaken about the nature of the contract. For example, a person who signs away the deed to a house, thinking that the document was only a guarantee for a debt, might be able to plead non est factum. Failure to read the terms of a contract will negate this defence.

Non-joinder: If a person who should have been a party to legal proceedings has been omitted, the court may amend the pleadings to include the non-joined party.

Nonfeasance: Not doing something that one is bound to do by law. Compare with misfeasance.

Novation: Substitution of a new contractual debt for an old debt by agreement between the debtor, the creditor and a third party who takes on responsibility for the original debt.

Nudum pactum: (Latin: an empty agreement) An agreement without consideration, such as a unilateral undertaking, which may bind a person morally, but not under contract law, unless the agreement is under seal.

Nuisance: Substantial unlawful use of one”s property or interference with another”s property to the extent of unreasonable annoyance or inconvenience to a neighbour or to the public. Private nuisance might be caused by smells, noise, smoke, dust, fumes, vermin, obstruction or a wide range of other activities or inactivity. The remedies would include abatement (an order to cease the nuisance), damages and/or an injunction.

Obligation – a requirement to take a particular type of action, that may have a legal basis through a contract.