binchy poo Share definition Flag a derivation of sweetie poo, which is a derivation of sweetie pie. calling someone a binchy poo is not an insult but rather a thing out of fondness. me: siena is the binchiest poo i know. siena: no, you're a binchy poo. binchy poo by tuckalow November 11, 2018 Get the binchy poo mug.