cool head

bang one's head against a brick wall

To waste effort on a futile project.

bash someone's head

To beat up someone violently.

big head

An inflated ego, an exaggerated belief in one's own importance.

bite someone's head off

To severely berate someone.

blow someone's head off

To shoot someone in the head.

bury one's head in the sand

To deliberately ignore the reality of a situation; to pretend a problem does not exist.

come to a head

To rapidly reach a turning point or climax.

cool cat

A person who performs or appreciates jazz, especially one whose style of speech and movement is relaxed and rhythmic.