Definitions from Black's Law Dictionary: 2nd Edition and Ballentine's Law Dictionary as are available for each term in each dictionary.
  • Ballentine's Law Dictionary

    One who furnishes information for the prosecution of a crime. See, also, Common informer.

  • Black's Law Dictionary: 2nd Edition

    A person who informs or prefers an accusation against another, whom he suspects of the violation of some penal statute.
    —Common informer. A common prosecutor. A person who habitually ferrets out crimes and offenses and lays information thereof before the ministers of justice, in order to set a prosecution on foot, not because of his office or any special duty in the matter, but for the sake of the share of the fine or penalty which the law allots to the informer in certain cases. Also used in a less invidious sense, as designating persons who were authorized and empowered to bring actions for penalties. U. S. v. Stocking (D. C.) 87 Fed. 861; In re Barker, 56 VL 20.