beat one’s brains out

beat (one's) brains out

1. To put forth one's maximum effort. I've been beating my brains out trying to get a passing grade this semester, so failing by two measly points is incredibly frustrating. Don't beat your brains out trying to please these people—they'll never appreciate it.
2. To physically attack one, as with punches and other blows, such that they suffer significant injury. This phrase can be used both literally and hyperbolically. I'm worried that the captain of the football team will beat my brains out if he finds out that I'm secretly seeing his girlfriend. As if I didn't feel bad enough after losing the case, my boss beat my brains out for it once I got back to the office.
See also: beat, brain, out
Farlex Dictionary of Idioms.

beat one’s brains out

verb
See beat one’s brains out to do something
See also: beat, brain, out
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • beat (one's) brains out
  • beat brains
  • beat brains out
  • beat one’s brains out to do something
  • beat one's brains out
  • beat someone’s brains out
  • beat your brains out
  • break (one's) back
  • break back
  • break your back doing something/to do something