An acronym used when someone who is being a major asshole who will not shut the fuck up (Shut Your God Damn Mouth ) (preferably used when texting)
Person 1 (you) : Dude shut up
Person 2: "dude shut up"
(You): come on man shut up
Person 2:"Come on man shut up"
(You): SYGDM
Person 2: "dude shut up"
(You): come on man shut up
Person 2:"Come on man shut up"
(You): SYGDM
by RangerRandom May 15, 2016