In a course of a conversation, one may say things that annoy the other, or say things that are true and the other person doesn't want to face that truth, so they respond with "gm".
Martin: "So, did you finish thisEnglish homework?"
Robin: "No."
Martin: "Why not? Too lazy to use your concious mind and get some primitive ideas down on paper?"
Robin: "gm, Martin, gm."
Good Mannered, a term most people use now a days online when they don't wantstupid ass people going into their channels on B.Net going "YOU SUCK DICK..." etc. etc.
Player 1: Hi, are you GM?
Player 2: FUCK NO
Player 1: Oh, then I don't want to game with you sorry...
Player 2: STFU nerd!
Player 1: >kick Player 2 manner please
Player 1 has kicked Player 2 out of the channel.
Any of a line of engineering abortions produced for the last hundred years or so. Similar to a medieval torture device, but without the quality. Any automobile belonging to the fecal genus.
My GM is such a steaming pile of feces, I can't bring my self to spend $10 on a car wash.
or
How unusual, there is a GM that still runs.
Stands for General Motors. Often used in shorthand as an umbrella term for its several brands (Chevrolet Pontiac Oldsmobile Buick Cadillac Holden Hummer Saturn GMC) etc.