Gm has 6 different meanings across 2 categories:
Noun · Intj
a metric unit of weight equal to one thousandth of a kilogram
Initialism of game master or game moderator.
Initialism of general manager.
To DM or practice Dungeon Mastering; to run a tabletop role-playing game.
Initialism of genetically modified.
Initialism of good morning.