1. Exhibiting or affected by being wasted, withered, or shriveled: "Because of the pain, the patient had an atrophied arm."

"The musician's lack of sufficient training revealed his atrophied talent."

2. With reference to a part of the body, to be reduced in size and therefore strength, or, more generally, to become weaker: "After months of sitting in front of the computer playing games for several hours each day, it was obvious that she had developed atrophied leg muscles which considerabliy handicapped her."
3. In pathology, a wasting or decrease in size of a body organ, tissue, or part because of disease, injury, or lack of use: "Paralysis of the teenager was the cause of his atrophied muscular condition."
4. A wasting away, deterioration, or diminution: "She was told that her atrophied intelligence was a result of not stimulating her mind enough."

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.

Simon significantly atrophied during his bedridden illness.

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

2. The degeneration, decline, or decrease, because of the lack of using something: Dr. Hughes, the professor, argued that freedom and independence of thought were progressively atrophying because too many people were simply ignoring their political rights.