1. A vile and mean slut, with little redemptive qualities.
2. The person everyone loves to hate.
3. A domineering and mean old bag who can be promiscious yet uses the promiscurity as a means of control, and making everyone else miserable.
As can be shortened to CW.
"That CW, Chelsea called while she was making out with my boyfriend just so she can rub it in what I was missing. What a CuntyWhore!"