Decadent movement
Decadence generally refers to a "process, condition, or period of deterioration or decline, as in morals or art; decay" (http://www.thefreedictionary.com). The Decadent Movement was a transitory, yet considerable late 19th-century literary style. In the decadent movement writers of the time expressed tabu-topics like sexual orientation or sex in general in their works, which was an absolutely new approach to literature in the negative sense. Some writers of the Decadent Movement called themselves "Decadent" but the term "Decadent" arose in the literary world as a disparaging assessment from critics, criticising and making fun of the repective writers. The probably most famous British Decadents were Oscar Wilde and Aubrey Beardsley. However, the term did not originate in the 19th century but
Sources
http://www.thefreedictionary.com/decadence
http://libcom.org/library/decadence-aufheben-2
http://www.english.uwosh.edu/roth/Decadence.htm
http://r.wisegeek.com/what-was-the-decadent-movement-in-literature.htm