cheststabber

A cheststabber is the polar opposite of a backstabber: That is, they'll tell you straight up that they dislike you. These people deserve more respect than a backstabber does. The cheststabber is remarkably better than the backstabber because cheststabbers have the courage to badmouth you straight up, unlike backstabbers who seem to be absolute cowards because they act like your friend, then go badmouthing you without you even knowing.

Dan: Far out, I hate that guy Ryan! Bloody goes calling me an asshole as soon as he laid eyes on me!
Me: This guy sounds like a cheststabber. I respect him, as I respect all cheststabbers. He had the balls to say what he thinks about you, he didn't back down.