can of whoopass Share definition Flag Retribution; or an act which manifests such. Commonly used in conjunction with the verb "to open up a". Also see whoop-ass and to get medieval on. Are you going to quit whining, or am I gonna have to open up a can of whoopass on you? can of whoopass by Sparkly Minx November 15, 2003 Get the can of whoopass mug.