Yes, brain is a Scrabble word!

Verb

1. Hit on the head

2. Kill by smashing someone's skull

Noun

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

2. Mental ability

3. That which is responsible for one's thoughts and feelings; the seat of the faculty of reason

4. Someone who has exceptional intellectual ability and originality

5. The brain of certain animals used as meat