The term 'COOL HEAD' can be broken down into three crossword solutions: POISE (5 letters), CEE (3 letters), and HARDC (5 letters). POISE is a noun meaning a dignified, self-assured manner or bearing. CEE is an abbreviation for the letter C. HARDC is an adjective meaning difficult to deal with or manage. Together, these three words form the phrase 'COOL HEAD, ' which is an idiom meaning to remain calm and composed in a difficult situation.