1. To waste away as a result of the degeneration of body cells: "Without adequate exercise, the muscles will atrophy regardless of one's age."

"The man significantly atrophied during his bedridden illness."

"Many elderly people have "sarcopenia" or atrophying of the muscles because either they don't exercise at all or not adequately. We are never too old to exercise!"

2. The degeneration, decline, or decrease, because of the lack of using something: "The professor argued that there was a progressive atrophy of freedom and independence of thought because too many people were simply ignoring their political rights."