Definition of pop a cap in his ass in the Idioms Dictionary. pop a cap in his ass phrase. What does pop a cap in his ass expression mean? Definitions by the largest Idiom Dictionary.
Feb 22, · pop a cap in (one's) ass: [verb] to shoot someone. I am going to pop a cap in your ass.
to shoot someone. Get a pop a cap in your ass mug for your Facebook friend Günter.
Ebonics for: "discharging a firearm into your body with the intent to cause grievous bodily harm".