GFYM Share definition Flag Go Fuck Your Mother! Also know as "The four words guaranteed to start a fight!" Use it when everyday insults, just won't do! Very much like GFY, only better. Hey Johnny, Go Fuck Your Mother! Or just GFYM GFYM by Rosslyn Maleman January 8, 2008 Words you can keep railfan mug chonk mug chud mug based mug 67 mug slime mug mogging mug chopped mug thot mug glazing mug huzz mug yams mug larp mug unc mug cracked mug simp mug baddie mug bop mug lolcow mug