In what ways do flappers of the 1920s reject nineteenth century gender roles?

In their social attitudes and in the way they defined what it meant to be a "woman," the flapper of the 1920s rejected 19th Century gender roles.

The flappers of the 1920s challenged the previous generation's understanding of what it meant to be a woman.  Prior to the 1920s, women were intended to be in the literal and figurative background.  They were meant to be seen and not heard.  Social mores dictated that women were...

In their social attitudes and in the way they defined what it meant to be a "woman," the flapper of the 1920s rejected 19th Century gender roles.

The flappers of the 1920s challenged the previous generation's understanding of what it meant to be a woman.  Prior to the 1920s, women were intended to be in the literal and figurative background.  They were meant to be seen and not heard.  Social mores dictated that women were to be docile and subservient. Even in their manner of dress, they were meant to assimilate to the culture around them. Dress length was to the floor and all skin was to be concealed.

The 1920s flapper was a different brand of woman.  She was meant to stand out from the crowd.  Dress length was much shorter, feather boas and other accessories distinguished her.  She was "liberated" in the way she carried herself, challenging men in the way she danced, flaunted sexuality, and in how she insisted on the very best.  The flapper wore makeup, sometimes carrying a flask of illegal alcohol in her garter belt.  She liked fast cars, loud dance music, and enjoyed attending the best parties.  

The flapper was also emboldened politically.  The 19th Amendment ensured women's suffrage and this helped to cross over into how the 1920s woman was fundamentally different than her predecessors.  The flapper enjoyed talking about others and enjoyed being the center of others' conversation. She was not part of the background.  She saw herself as the foreground and everything in it.  Independence became central to women's identity. In the process, Victorianism was set aside for this new brand of woman that defined so much of the 1920s.