Grease Boi Share definition Flag Kids who don't shower often, and have oily foreheads and greasy hair. 1:Damn that kid stinks. And his hair, it's so greasy! 2: Thats because hes Grease Boi Grease Boi by PoopPant March 13, 2018 0 0 Get merch Get the Grease Boi mug. Buy Now — $32.95 See more merch