Progressive decline is a term used to describe a gradual decrease in the quality or quantity of something over time. It can be seen in physical objects, such as atrophying muscles, or in abstract concepts, such as decaying relationships. The two crossword solutions for this term are atropy (7 letters) and DECAY (5 letters). Atropy is the wasting away of muscle tissue due to lack of use, while DECAY is the gradual deterioration of something over time. Both of these words accurately describe the concept of progressive decline.