So why don't I just tell a girl I barely know she's a psychopath?
Huh? You want to do what? Why would you call her that?
Because she was being an asshole to me
You should not call her names though, even if you are not getting along. Names like that can really hurt someone.
I'm looking to get into an argument
Name calling is very mentally abusive, did you know that? Yes, it is and if you go ahead with it you will argue and things will get ugly. Stay calm and be nice to others, even if they are not nice to you because you are bigger than that.