Fat Bastard-itus Share definition Flag (Noun) A person who is very obese.The persons’ name is usually Darren, Jamie and Steven. “You have Fat bastard-itus!” Fat Bastard-itus by Tway Ubabqwe February 22, 2020 0 0 Get merch Get the Fat Bastard-itus mug. Buy Now — $32.95 See more merch