front-butt Share definition Flag (Noun) A belly that is so large that it hangs low and has an apparent vertical crease resembling that of a buttocks. "That guy is so fat he has a front-butt and he looks like a plumber walking backwards" front-butt by Taross January 9, 2007 0 0 Get merch Get the front-butt mug. Buy Now — $32.95 See more merch