Flappers were a new "breed" of young women who came of age in the 1920s. They drove, drank, smoked, dressed provocatively and had causal sex, setting them apart from the traditional woman of the early part of the century. Typically, they were heavy listeners of jazz. The 1920 movie "The Flapper" was credited with popularizing the name and the lifestyle of the term.
From Positive Jam