a psycho bitch is that girl that walks up to you at a party, as soon as your girl turns her back, and is like "your soo hot, wanna make out?" then, after telling her your girlfriend is right over there, she says, "oh, well, i don't wanna mess things up with you and your girl, but we can do anything you want..." as she runs her finger down your chest and hooks it in your belt. then, after you politely decline, because you're not tryin to have this psycho bitch get all pissed and start gettin crazy on your ass, she follows you to the beer pong table like she's your personal cheerleader or some shit. in summation, she's that bitch that can't take a hint when one smacks her in the face.
dirty slut probably had diseases...