'堕落' (duòluò) is a compound noun meaning 'moral decline' or 'degeneration'—a gradual deterioration in ethical character, values, or behavior. Though each character individually can mean 'to fall' (堕) and 'to descend' (落), together they form a fixed, abstract term that emphasizes a downward moral trajectory, not physical falling. It carries strong negative connotations and is often used to describe a person’s loss of integrity, spiritual decay, or abandonment of social or cultural standards.

The word appears frequently in formal writing, moral education, religious discourse, and social criticism. It implies intentionality or vulnerability to temptation rather than mere misfortune—it suggests a conscious or passive slide away from virtue, responsibility, or discipline. While it can describe individuals, it's also applied metaphorically to institutions, societies, or artistic movements perceived as losing their original ideals or authenticity.