beat sb's brains out INFORMAL
to hit someone repeatedly with great force

[TahlilGaran] Advanced Learner's Dictionary ▲

beat brains out
beat (someone's) brains out
1.
to severely criticize someone.
How could I win the election with that guy on the radio beating my brains out every day?

2.
to seriously hurt someone.
I was afraid he was going to come back and beat my brains out.

beat (your) brains out
to spend a lot of time worrying about a problem and thinking about how to deal with it.
I've been beating my brains out trying to think of a way of getting the money to her in time.
(often + doing something)

[TahlilGaran] English Idioms Dictionary ▲

beat someone's brains out
beat (someone's) brains out
1.
to severely criticize someone.
How could I win the election with that guy on the radio beating my brains out every day?

2.
to seriously hurt someone.
I was afraid he was going to come back and beat my brains out.

beat (your) brains out
to spend a lot of time worrying about a problem and thinking about how to deal with it.
I've been beating my brains out trying to think of a way of getting the money to her in time.
(often + doing something)

[TahlilGaran] English Idioms Dictionary ▲

beat one's brains out
1. to tire oneself by thinking too much
I have been beating my brains out all day trying to remember where I put my notebook.

2. to work very hard (to do something)
We beat our brains out in order to think of a name for the new magazine.

[TahlilGaran] English Idioms Dictionary ▲

beat one's brains out
v. phr., slang To try very hard to understand or think out something difficult; tire yourself out by thinking.
It was too hard for him and he beat his brains out trying to get the answer.
Some students are lazy, but others beat their brains and succeed.

[TahlilGaran] English Idioms Dictionary ▲