1.NounThe anus; often in reference to anal intercourse.
"She likes it up the pooper."
2.NounOne who poops out on an activity; one who dampens the mood by lack of participation or negative attitude. Mostly used in the phrase party pooper.
"I wanted us to have fun today. You're such a pooper cleaning the house now!"
3.NounA selection in a slot machine game that ends the picking bonus.
4.NounOne who poops; or, poops well.
"Jimmy's toilet training is finally over; he's becoming a good little pooper."