GM is an abbreviation of ‘Grand Master’ and refers to the most exclusive and highest-rated ladder tier by Blizzard, reserved only for the top 200 players in any given region. Reaching GM is considered to be a crowning achievement for any casual gamer.
In WoW and other MMORPGs, GM can also stand for Game Master.
‘GM’ and ‘Grand Master’ Gaming Slang Term Worldwide Use Trend
