break the fourth wall

back to the wall

A very difficult situation with no beneficial options available for action.

balls to the wall

With maximum effort or commitment.

bang one's head against a brick wall

To waste effort on a futile project.

big break

A breakthrough, especially the first big hit of a previously unknown performer or performers in the entertainment industry.

blue wall of silence

Strict secretiveness maintained by the members of a police force with respect to information which might be contrary to their interests, especially information concerning questionable police actions.

break a leg

Good luck!; Do your best!; Said to someone wishing they perform well in a theatrical production or comparable endeavor.

break a sweat

To put effort into something.

break cover

To disclose one's real thoughts and intentions.