brain

That which is responsible for one's thoughts, feelings, and conscious brain functions; the seat of the faculty of reason.

Mental ability.

“he's got plenty of brains but no common sense”

Someone who has exceptional intellectual ability and originality.

That part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord.

The brain of certain animals used as meat.

Hit on the head.

Kill by smashing someone's skull.