brains

The control center of the central nervous system of an animal located in the skull which is responsible for perception, cognition, attention, memory, emotion, and action.

An intelligent person.

“She was a total brain.”

(in the plural) Intellect.

“She has a lot of brains.”

By analogy with a human brain, the part of a machine or computer that performs calculations.

“The computer's brain is capable of millions of calculations a second.”

Oral sex.

Mind.

“I have too much on my brain today.”

To dash out the brains of; to kill by smashing the skull.

To strike (someone) on the head.

To destroy; to put an end to.

To conceive in the mind; to understand.

The substance of a brain as a material or foodstuff.

The figurative substance of a brain: mental ability, intelligence.

“Sadly, I got my brains from my mom and my looks from the mailman.”

(with 'the') The intelligent person or people in a group: the director, planner, administrator, &c.

“Who's the brains behind this operation?”