The term 'NOT FIRST' can be broken down into two crossword solutions: LAST (4 letters) and TAILING (7 letters). The word LAST is an adjective that means coming after all others in a sequence or series. It is often used to refer to the final item in a list or group. The word TAILING is a verb that means to follow or come after someone or something. It is often used to describe the action of trailing behind someone or something.