The term UNWILLING TO GIVE IN can be summarized by the crossword solution ADAMANT, which is a seven-letter word. ADAMANT is an adjective that means firmly determined or resolute and unwilling to change one's mind or course of action. It is derived from the Greek word 'adamastos, ' which means 'UNCONQUERABLE.' This term is often used to describe someone who is stubbornly refusing to give in to another person's demands or requests.