atrophy

如果长期不锻炼，肌肉就会逐渐萎缩。

Muscles will ___atrophy if you don't exercise them regularly.

如果长期不练习，语言能力会退化。

Language skills ___atrophy if you don't practice them regularly.

多年来疏于联系，他们的友谊逐渐消退了。

Their friendship slowly ___atrophied after years of neglected messages and missed calls.