same as bumpin
bumpin is to describe a person with loud ass subs while pumpin is a person without subs that turn it up loud
being used recently in the projects
damn dawg, that foo's car be pumpin.
fo sho homie, sounds decent for not having subs.
Sellin drugs or slangin
"He be pumpin on your block, ya man gave em your glock.."
Nas 1994; Illmatic- One Love