adj. - a girl that has had sex with many different men. In other words, many guys have deposited their "Johnson's" in her "bank." This term is reserved for the sluttiest girls you know.
Friend 1: "Hey, have you seen that girl that always wears those really short booty shorts around campus?"
Friend 2: "Oh yeah! She has had sex with all of the guys on the basketball team... She's a real Johnson Bank"