fat mouthing Share definition Flag talking trash, talking shit, talking out ones ass, fronting The niggah wasn't saying anything ta yo until youz put in the back of the hot-boys car, then he wouldn't stop fat mouthing about you. fat mouthing by Blindflight April 25, 2006 0 0 Get merch Get the fat mouthing mug. Buy Now — $32.95 See more merch
