The term 'not cool at all' can be described by four five-letter crossword solutions: NERDY, TENSE, UNHIP, and DORKY. NERDY is an adjective used to describe someone who is overly interested in intellectual or academic pursuits. TENSE is an adjective used to describe someone who is anxious or nervous. UNHIP is an adjective used to describe someone who is not fashionable or up-to-date with trends. Finally, DORKY is an adjective used to describe someone who is socially awkward or clumsy. All of these words are used to describe someone who is not cool at all.