退化

Verb

 * 1) to degenerate; to atrophy
 * 2) to deteriorate; to worsen; to decline; to fall; to drop

Usage notes
is used to emphasize a good situation turning bad, while is used to emphasize corruption and degeneration.

Noun

 * 1) degeneration; retrogression

Verb

 * 1) to degenerate, to retrogress