moral decadence; moral decline; moral corruption
Refers to a state or process of moral decay in society, culture, or individuals. Often used in critical or analytical contexts.
The moral decadence of modern society is seen as a problem.
He lamented the moral decline of young people.
退廃 means 'decadence' or 'degeneration' in a broader sense, while 道徳退廃 specifically refers to moral decay.
道徳 means 'morality' or 'ethics'; 道徳退廃 is the decline or corruption of that morality.
Compound of 道徳 (morality) and 退廃 (decadence, decline). The exact historical derivation is uncertain, but the combination transparently conveys moral decay.