A girl said she would steal a boyfriend from a girl just because she thinks that other girl is ugly. Now she is mad that I called her a whore. How do I make her feel even worse?

Lookism is a form of prejudice. Clearly the boyfriend of the so-called “ugly” girl has no problem with her looks. The girl who has a problem with someone else’s looks, conventionally attractive or not, has a problem with herself. Is she that insecure that she needs validation from someone else’s boyfriend?

Regardless, responding with whorephobia was not the way for you to go. Prejudice against sex and sex workers is a more virulent form of bigotry that hurts those workers specifically but all overtly sexual people in general, especially girls, women, and female-appearing people. Being sexual is not the namecaller’s problem. Being an insensitive and insecure jerk is.

You both need to do much, much better.