When you verbally rip somebody to shreds so bad it is like slapping them across the face.
I just gave Connor a pretty good verbal backhand while playing Call of Duty.
When you dis somebody so badly that they feel like they were backhanded by words.
Alex: Your hair looks weird Phillip!
Phillip: You look like a bus ran over your face then put it in reverse just to make sure they got the job done. Followed by a pack of ninjas slicing you into bite size pieces.
Anybody within earshot: DAYUM ALEX JUST GOT VERBALLY BACKHANDED!!!