GFYMF Share definition Flag Could mean either "Good For You My Friend" or "Go Fuck Yourself Mother Fucker". Depends on which situation you are in to reach the desired results. Christian: Did you see my hole in one! Burt: GFYMF! Christian: Good for you my friend? GFYMF by BdubCav August 20, 2015 0 0 Get merch Get the GFYMF mug. Buy Now — $32.95 See more merch