Flappers

F. Scott Fitzgerald first used the term flappers to the U.S. to describe the image and style of the new style. He described them as "lovely", "expensive", and about "nineteen". The flapper image was young girls wearing unbuckled galoshes that would make a "flapping" noise when walking. Flappers usually wore short skirts, bobbed their hair and listened to jazz. They also wore excessive makeup ,drinking, smoking( which women usually never did), and treating sex in a casual manner as well as dancing the charleston.

In The Great Gatsby Jordan Baker is an athletic, independent woman who maintains a moral lifestyle. Her character represents the new breed of woman(flappers) in America with a sense of power. The term Flapper first appeared in Great Britain after WWI it was used to describe young girls still some what in movement who had not yet entered womanhood.

http://history1900s.about.com/od/1920s/a/flappers.htm
by Jennifer Rosenberg, About.com Guide