The backwards path of a female's puberty. She once had tits but got a lot thinner and somehow lost her boobs. We are unaware of why this occurs all we know is that it does occur.
Dude 1: Dude, what happen to that chick? Her tits used to be fuckin huge and her ass was amazing!
Dude 2: Man, I don't know. Bitch went through depuberization last summer.