tuì​huà

atrophy

退化 tuì​huà
atrophy verb
to lose function, size, or structure in an organ or organism through evolutionary or physiological processes

Due to living in darkness for a long time, the eyes of this fish species have degenerated.

degenerate verb
to decline or deteriorate from a higher or more complex state to a lower or simpler one

If you don't practice regularly, your language skills will gradually decline.

Frequency

Movie subtitles
2.30 per million appears in 1% of films
Written text
4.25 per million

Sources

Definitions
CC-CEDICT