short for "straight up gangster" as defined by our very own Forefathers at Lowell HS c/o 07. an abbreviation often tagged on book covers and class notes and spoken only in your best napoleon dynamite voice. makes sure your nose is nice and scrunched up and your eyes remain fairly squinty.
o man! look at that guy with the gray and red ecko fit. its so hot today. what is he thinking? he's s.u.g. don't worry about it.