Nasty bitches are known for their extremely disgusting properties and abilities. They are the most repulsive type of women out there, usually robustly overweight along with many other gross attributes. If I had to describe them in a word or two I'd say: Pure Filth.
Johnny: So Dillon I heard you like fucken NASTY ass bitches.
Dillon: Fucken A' my nigga, the nastier the better... they're easy game, man. In fact, I'm dating a nasty bitch named Tiffany and she's 575 lbs. of FREAK!
The definition of a girl who really just makes you feel nauseated when seeing/thinking of/hearing of. Probably ugly, probably fat, stay away from these girls as your friends will laugh about you behind your pathetically-desperate-as-shit back.
nigga #1: Dude, that girls fucking sickening, I can't believe you're dating her.
nigga #2: You're just jealous. I know you used to like her!
nigga #1: What the fuck is wrong with you, you desperate-retarded-piece of shit. Don't try and make yourself feel better by thinking I'd date a fucking overweight nasty bitch like that! That's you! L-O-fucking-L.