G - Greasy, A - Ass, M - Monkey. A person suggestive of grease in slickness or slipperiness. Seen mostly on human hair or skin. A person with G.A.M usually struggles to be included but is often avoided by fellow peers.
examples of G.A.M's include: Michael Vick(speed), Michael Jordan(hangtime), Adam Gilchrist(hitting power), Andrew Johns(ball-playing), Chris Judd(raw talent) and many more