The term 'dealbreaker' is used to describe a situation in which an agreement or negotiation between two parties fails due to one party's refusal to accept the other's terms. In this context, the crossword solution for the term 'DEALBREAKER' is NARC, which stands for 'National Association of Realtors and Certified Appraisers.' This organization is responsible for setting standards and providing education and certification for real estate professionals.