a fancy smancy way of saying doche bag, when one wishes to be formal but still express that a person is bein an absolute dick, asshole, vagina, anus face, pussy, but licker, tool and all round fuck.
Person 1: Hey! You see the kid playing ping pong over there?
Person 2: Yeah. The one with greasy hair.
Person 1: He came over the other day. He's a complete dossé bagg.
Person 2: What? You mean like Marc?
Person 1: No. Like a complete DOSSE BAGG!