Definition of "flapper"

Stud's eyes roved. Plenty of girls, most of them young flappers, Loretta's age. Only a couple of years ago they were kids.

1934, James T. Farrell, chapter 16, in The Young Manhood of Studs Lonigan

I paid violent and unusual attention to a flapper all through the meal in order to make you jealous. She's probably in her cabin writing reams about me to a fellow-flapper at this very moment.

1910, Saki [pseudonym; Hector Hugh Munro], “The Baker’s Dozen”, in Reginald in Russia and Other Sketches, London: Methuen & Co. […], page 107

"Now," said the young man cheerfully to Ardita, who had witnessed this last scene in withering silence, "if you will swear on your honor as a flapper—which probably isn't worth much—that you'll keep that spoiled little mouth of yours tight shut for forty-eight hours, you can row yourself ashore in our rowboat."

1920 May 27, F[rancis] Scott Fitzgerald, “The Offshore Pirate”, in Flappers and Philosophers, New York, N.Y.: Charles Scribner’s Sons, published September 1920, page 13

Concern—and consternation—about the flapper are general. She disports herself flagrantly in the public eye, and there is no keeping her out of grown-up company or conversation.

1922 April 16, Margaret O'Leary, “More Ado About the Flapper”, in The New York Times‎

F. Scott Fitzgerald is best known as a chronicler of the 1920s and as the writer who, more than any other, identified, delineated, and popularized the female representative of that era, the flapper. Though it is an overstatement to say that Fitzgerald created the flapper, he did, with considerable assistance from his wife Zelda, offer the public an image of a young woman who was spoiled, sexually liberated, self-centered, fun-loving, and magnetic. […] Although she is often seen now as a mere fashion of the bygone Jazz Age, the flapper should be regarded as one of the great authentic characters in American history.

2002, Rena Sanderson, “8: Women in Fitzgerald's Fiction”, in Ruth Prigozy, editor, The Cambridge Companion to F. Scott Fitzgerald, page 143

Among McPherson's most passionate and visible advocates were Southern California's young flappers, who turned out in droves to cheer on the evangelist. While most fundamentalists vehemently criticized flappers, viewing them as symbols of moral decay and the decline of Victorian gender identities, McPherson had embraced them. Critics of her Bible college identified the young female ministers with whom she surrounded herself not as holdouts to Victorianism, but as outright flappers. The press even dubbed one of McPherson's most successful young protégés the flapper evangelist.

2009, Matthew Avery Sutton, Aimee Semple McPherson and the Resurrection of Christian America, page 125

It seems the minds of these people are so taken up with intense speculations, that they neither can speak, nor attend to the discourses of others, without being roused by some external taction upon the organs of speech and hearing; for which reason, those persons who are able to afford it always keep a flapper (the original is climenole) in their family, as one of their domestics; nor ever walk abroad, or make visits, without him. And the business of this officer is, when two, three, or more persons are in company, gently to strike with his bladder the mouth of him who is to speak, and the right ear of him or them to whom the speaker addresses himself. This flapper is likewise employed diligently to attend his master in his walks, and upon occasion to give him a soft flap on his eyes; because he is always so wrapped up in cogitation, that he is in manifest danger of falling down every precipice, and bouncing his head against every post; and in the streets, of justling others, or being justled himself into the kennel.

1726 October 28, [Jonathan Swift], Travels into Several Remote Nations of the World. […] [Gulliver’s Travels], volume II, London: […] Benj[amin] Motte, […], part III (A Voyage to Laputa, Balnibarbi, Glubbdubdribb, Luggnagg, and Japan)

Small fish, and frog and fish spawn are also eaten, and the ducklings feed upon many species of animalculæ, flies, pollywogs and worms, etc., disturbed by heavy rains which wash the banks, while the young ducks are passing to the "flapper" stage.

1904, F. Henry Yorke, "Our American Game Birds: Their Life History and Mode of Hunting Them," Field and Stream, Vol. 9, no. 3 (July 1904), pp. 255—56

the flapper of a porpoise

1876, Arabella B. Buckley, A Short History of Natural Science and of the Progress of Discovery from the Time of the Greeks to the Present Day

It was still too shallow for the turtle to swim, but it used its four flappers with so much effect against its two assailants, as to give them a thorough shower-bath.

1878, William H. G. Kingston, The Three Admirals‎, page 46

In this case, slide the collar of the flapper over the overflow tube until it seats against the bottom of the flush valve.

2004, David Day, Albert Jackson, Popular Mechanics Complete Home How-to, page 356