A grunge fringe is a hairstyle, but not one you usually will have on a voluntary basis. It is found on beings with a fringe, who haven't cut their hair in an a bit to big amount of time, and hasn't washed it in a while either. It can often be found amongst punks and such whom has had a bad month. A classic grunge fringe has usually some unnatural, but fading colours.
Kurt Cobain had a grunge fringe at times, but he seemed to want it...