jack-jawed - Punching someone so hard their jaw looks like it's about to

Punching someone so hard their jaw looks like it's about to take a vacation.

I got jack-jawed by my boss. Now my jaw is on strike.

My little brother got jack-jawed by the school bully. He’s got a black eye and a broken jaw.

At the gym, some meathead jack-jawed me. Now my jaw is sore and I’m out of breath.