figurative. intransitive. To decline or decay, esp. morally or socially; to diminish towards extinction, go to waste; (also formerly) †to perish…

intransitive. To turn aside from the right course; to be led astray; spec. to become a religious pervert. Now rare.

intransitive. figurative. To become morally corrupt; to decline in quality, purity, or power. Also: †to promote corruption or impurity (obsolete).

of moral decay.

figurative and in figurative contexts. intransitive. To become corrupted or rotten; to fester.

intransitive. To grow or become bad or depraved; to suffer corruption. Obsolete. rare.

To exhibit or savour of moral (artistic, etc.) decay. Of persons: also, to be despicable or completely incompetent. Of actions, phenomena, etc.: also…