douchebag

"douchebag" literally derives from the term associated with someone filling a paper bag with feces, either their own or of an animal, and then proceeding to set that bag on fire and leave it on a doorstep of someone's house who is deserving of such a gift.

If the term "douchebag" is said ABOUT a person it is the equivalent of calling them a flaming bag of poop.

"Ben is a total douchebag for hitting on Samantha when he knows I wanted that hot mess."