Coined in Blade: Trinity by Ryne Renolds' character; Hannibal King, the term is often used to describe types of people the word 'cunt' simple doesn't describe well enough.
Thunder Cunt describes a person so cuntish that it is as if the Thunder God himself had thrown a bolt of lightning into an infected vagina, spread the infection to the brain of said person, leaving them a disastrous, miserable, lonely peice of shit.
is a Thunder Cunt"
you're a mother fucking Thunder Cunt fagoot piece of shit"
Yeah man, that guy Ed Davison
is the biggest fucking Thunder Cunt in the entire world"