An over-enthusiastic, dumb, naieve, annoying, loud, squealy, MTV generation teenage chick that will do anything stupid to be the center of attention. Everyone's brother, cousin, boyfriend, best friend has dated or slept with one- and regretted it.
-That bippytwat is gonna get it if she doesn't get her hands off my boyfriend.
That dumbass bipppytwat girlfriend of yours has got your ass WHIPPED!
party girl, sorority girl, shallow girl. Plural form, bippytwats. Can not be used as an adjective. More often used in place of a proper noun when speaking of materialistic women, aged 13-29 years old.
"I'm down to earth, I don't hang out at malls or talk about shoes like a bippytwat."
"All that bippytwat ever wears is pink."