game-master

Noun

game master (plural game masters, abbreviation GM)

1. A person (especially a man) conducting a game.
   • Using only meaning-laden glances or other undetectable gestures, the Mafia members indicate to the game master which villager they’d like to off.2007 November 4, Heidi Julavits, “Parlor Tricks”, in T: The New York Times Style Magazine, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 01 Oct 2013
   1. (roleplaying games) A person (especially a man) conducting a role-playing game, generally responsible for controlling all beings and processes other than the players, either individually or as part of a team.