Meaning

noun a young woman in the 1920s who flaunted her unconventional conduct and dress

originpossible etymologies Possibly from Victorian sporting slang, meaning young wildfowl in August which are full-sized, tender and worthwhile quarry, but are naive and unable to fly properly due to the late development of flight feathers in ducks and geese. Alternative derivations are also suggested. The word "flap" was slang in the 17th century for a prostitute: by the late 19th century in England…

Etymology from Wiktionary, CC BY-SA 3.0