beat 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.
beat someone's brains out
1. to hit or batter someone severely. She threatened to beat my brains out. Those thugs nearly beat his brains out.
2. to drive oneself hard (to accomplish something). I beat my brains out all day to clean this house, and you come in and get dirt on the car-pet! Don't beat your brains out. Just give it a good try.
beat one's brains out (to do something)
to try very hard to do something. If you think I'm going to beat my brains out to do this, you are crazy. I beat out my brains to do this for you! Iwon't beat my brains out again for you!