1. Something you shit out, you can get big ones, runny ones or little pellet things (can be hard to flush). 2. Term of abuse, as in: "That Hitler was a real poo." 3. sometimes with the suffix 'f', meaning a gay man. (Shak) A poo, a poo, my kingdom for a poo. Endlessly amusing especially if you're a boy or if you spell all day long writing boring fucking dictionary definitons.
Poo is used as a Suffix to someones Name when that person, being full grown and capable of taking care of themselves, still sponges off their parents or still lives with their parents.
Poo can also be used individually with reference to the same situation.
Really, you still live withyour parents? You are such a poo! or Person A: "Gareth is 27 and still lives with his Parents?"Person B: "I know! He's such a Gareth-Poo!"