The term 'Ax to Grind' is an idiom that means to have a personal AGENDA or motive. It is derived from the idea of sharpening an ax before using it, implying that someone has a plan in mind and is preparing to act on it. The crossword solution for this term is 'AGENDA', which is a noun meaning a list of matters to be considered or done. This term is often used to refer to a person's plans or intentions, especially when they are hidden or not obvious.