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.