beat someone’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 violently attack someone, physically or verbally. 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

beat someone’s brains out

1. tv. to beat someone severely. She threatened to beat my brains out.
2. tv. to drive oneself hard (to accomplish something). I beat my brains out all day to clean this house, and you come in and track up the carpet!
See also: beat, brain, out