A public officer charged with carrying on the prosecution or representing the state in criminal proceedings and, in some jurisdictions, instituting or representing the state in civil or administrative proceedings.

A common law intentional tort which arises from a party (1) intentionally and maliciously instituting or pursuing (or causing to be instituted or pursued) a legal action (civil or criminal) that is (2) brought without probable cause and (3) dismissed in favor of the other party.

(law) In United States patent law, the circumstance under which a person who has filed a patent application, and then made amendments to the application to accommodate the patent law and secure issuance of the patent, is prevented from bringing a cause of action for infringement of the patent where the allegedly infringing acts falling within the matter disclaimed by the amendment.