Pop jaw

Where your one or both sides of your jaw makes a poping sound when you open your mouth wide enough.Most often heard when someone yawns. People are usually born with this condition.

I didn't know he had a pop jaw.

by Deep blue 2012 April 19, 2010

popping your jaw

To make a physical threat without following through.

Keep on popping your jaw, you're too big of a pussy to throw one punch.

by Staples8 November 22, 2014