poopybutt Share definition Flag the best insult in the world to really get to your younger siblings. younger sibling: *comes into your room and invades your privacy* you: GET OUT YOU POOPYBUTT poopybutt by Ya Gurl Vv April 30, 2020 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