the.com/flapper

means A young woman of the 1920s who bobbed her hair, wore short skirts, danced to jazz, and generally threw out the rulebook on how 'respectable' women were supposed to behave.

from Before it meant a liberated jazz-age woman, 'flapper' was British slang for a young girl, possibly evoking a fledgling bird flapping its wings before it can really fly — or, in another thread, linked to the loose, unfastened boots or hair-ribbons young girls wore, left to flap as they walked. By the early 20th century it had drifted into describing lively, unconventional young women, and the 1920s press seized it for the new breed of short-skirted, cigarette-smoking, dance-mad women defying old norms — the word flapping free right along with them.