A combination of the words friend and predator
A creepy ex girlfriend or boyfriend. A obsessive
girl or
guy whom is that into you. The kinda person you can call a fangirl or fanboy of plain ole you.
Note the person doesnt necessarily have to be an
ex. It can be someone who just doesnt take no. The friend who gets too close in a creepy way.
A similar word is yandere.
In
japan see : Kotonoha Katsura, yuno gasai
In the usa see: knives chau