A girl that lacks morals. She has had many sexual encounters with the opposite sex and possibly has an STD. These girls tend to sleep with everyone with the exception of their boyfriend. These girls are also flirty, and they often treat guys in a greasy manner. The girls that do this often do it to boost their ego. Basically another word for the common slut.
Joe: I heard that girl has dick sucking marathons with her roommate.
Kieth: Yeah man. I wouldn't be surprised if she has something. Shes a slogg.