Decadence (pronounced: DEK-a-dence) means a state in which people are behaving in a way that is regarded by some people as being morally bad. The adjective is 'decadent'. It has nothing to do with the word decade (10 years).

“Decadence” comes from the Latin words “de” (from) and “cadere” (to fall). Thus it means to fall from a higher state of being.

Decadence is usually a state in a society which used to be good but has become bad. Many people have started to behave in a way that others think is shocking and society does not function as well as it did before. Of course, not everyone will agree what is “good” or “bad”, but some societies, such as Sodom and Gomorrah, are thought to have been decadent.

The end of the 19th century and beginning of the 20th century is often called the fin de siècle (end of century). It is an example of a supposed decadent society in literature and art.

In France there were several writers who were happy to be called “decadent”. They included Paul Verlaine, Charles Baudelaire, Arthur Rimbaud and Stéphane Mallarmé. In France, the symbolist artists such as Gustave Moreau regarded themselves as "decadent". In England decadent artists included the author Oscar Wilde and visual artists such as Aubrey Beardsley. The "decadents" advocated living a "decadent lifestyle", which means a lifestyle based on seeking the maximum possible amount of aesthetic pleasure.

In the early 1970s, glam rock musicians such as David Bowie called themselves "decadent". David Bowie's 1973 album Diamond Dogs is about the theme of decadence. Glam rock musicians and fans of glam rock music signaled that they were decadent by wearing platform shoes. The popular 1976 film Rocky Horror Picture Show was a humorous depiction of "decadence".

People of the goth subculture, which began in the early 1980s among fans of the band Bauhaus, generally regard themselves as being "decadent". One way they may symbolize themselves as being decadent is by wearing fishnet stockings.

The color lavender is usually used to symbolize decadence. Both of the books in the "further reading" list below are colored different tones of lavender. In the 1890s, the color mauve was used to symbolize decadence--the 1890s were called the mauve decade.

• Decadence: the strange life of an epithet By Richard Gilman--New York: 1979--Farrar, Straus and Giroux
• Dreamers of decadence: the symbolist painters of the 1890s By Philippe Julian 1971