1. a presumed deterioration of a culture, society, or civilization because of a general collapse of moral character and traditional values.

2. generally, a loss or diminution of excellence or some other quality.

3. (typically capitalized) loosely, an artistic movement of the mid- and late 19th century, particularly in literature and the visual arts, that valued extreme aesthetic refinement, the superiority of artifice (i.e., human invention) over nature, and innovative and atypical experiential perspectives and modes of being. Also called Decadent movement.