The term 'cooler head' can be represented by two crossword solutions: WARDEN (6 letters) and JAILER (6 letters). A WARDEN is a person who is responsible for the supervision of a prison or other correctional facility. A JAILER is a person who is responsible for the custody and care of prisoners in a jail. Both roles involve maintaining order and security in a correctional facility, and both require a cooler head to ensure that justice is served.