A Chicago variation of the terms "mug" and "mark." Essentially it is a word that can be used like the pronouns "dude" or "cat," and almost always in the third person. Not as negatively connotated and indicitive of victimization as "mark."
-"I was on the Garfield stop platform when this smelly-ass faggot marg came up to me asking if he could get dollar."
-Somebody says something stupid and somebody else responds, "thiiiiiiiiiiiiiis marg..."