See more synonyms for flap on Thesaurus.com
verb (used without object), flapped, flap·ping.
  1. to swing or sway back and forth loosely, especially with noise: A loose shutter flapped outside the window.
  2. to move up and down, as wings; flap the wings, or make similar movements.
  3. to strike a blow with something broad and flexible.
  4. Slang. to become excited or confused, especially under stress: a seasoned diplomat who doesn't flap easily.
verb (used with object), flapped, flap·ping.
  1. to move (wings, arms, etc.) up and down.
  2. to cause to swing or sway loosely, especially with noise.
  3. to strike with something broad and flat.
  4. to toss, fold, shut, etc., smartly, roughly, or noisily.
  5. Phonetics. to pronounce (a sound) with articulation resembling that of a flap: The British often flap their r's.
  1. something flat and broad that is attached at one side only and hangs loosely or covers an opening: the flap of an envelope; the flap of a pocket.
  2. either of the two segments of a book jacket folding under the book's front and back covers.
  3. one leaf of a folding door, shutter, or the like.
  4. a flapping motion.
  5. the noise produced by something that flaps.
  6. a blow given with something broad and flat.
  7. Slang.
    1. a state of nervous excitement, commotion, or disorganization.
    2. an emergency situation.
    3. scandal; trouble.
  8. Surgery. a portion of skin or flesh that is partially separated from the body and may subsequently be transposed by grafting.
  9. Aeronautics. a movable surface used for increasing the lift or drag of an airplane.
  10. Phonetics.
    1. a rapid flip of the tongue tip against the upper teeth or alveolar ridge, as in the r-sound in a common British pronunciation of very, or the t-sound in the common American pronunciation of water.
    2. a trill.
    3. a flipping out of the lower lip from a position of pressure against the upper teeth so as to produce an audible pop, as in emphatic utterances containing f-sounds or v-sounds.
  11. Building Trades.
    1. Also called backflap hinge, flap hinge.a hinge having a strap or plate for screwing to the face of a door, shutter, or the like.
    2. one leaf of a hinge.

Origin of flap

1275–1325; Middle English flappe a blow, slap, flappen to hit, slap; compare Dutch flap, flappen
Related formsflap·less, adjectiveun·flap·ping, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for flapping

flail, flop, dangle, hang, vibrate, thrash, flash, beat, shake, agitate, wave, wag, lop, swish, thresh, swing

Examples from the Web for flapping

Contemporary Examples of flapping

  • Wingnuts were flapping their wings when far-left liberals got all misty-eyed talking about “Uncle Joe” Stalin.

    The Daily Beast logo
    America's 9 Worst Demagogues

    John Avlon

    September 2, 2010

Historical Examples of flapping

  • The sails had fallen off and they were flapping and thumping and clapping in the wind.

  • The cabman had put up his torch and was flapping his arms under his armpits.

    A Son of Hagar

    Sir Hall Caine

  • He raised his head with a noise in his ears that was like the flapping of wings in the dark.

    The Manxman

    Hall Caine

  • "There you are," said Pete, flapping the letter on one hand.

    The Manxman

    Hall Caine

  • Roger thought of his torn flag, flapping in the wind on the top of the flagpole.

British Dictionary definitions for flapping


verb flaps, flapping or flapped
  1. to move (wings or arms) up and down, esp in or as if in flying, or (of wings or arms) to move in this way
  2. to move or cause to move noisily back and forth or up and downthe curtains flapped in the breeze
  3. (intr) informal to become agitated or flustered; panic
  4. to deal (a person or thing) a blow with a broad flexible object
  5. (tr sometimes foll by down) to toss, fling, slam, etc, abruptly or noisily
  6. (tr) phonetics to pronounce (an (r) sound) by allowing the tongue to give a single light tap against the alveolar ridge or uvula
  1. the action, motion, or noise made by flappingwith one flap of its wings the bird was off
  2. a piece of material, etc, attached at one edge and usually used to cover an opening, as on a tent, envelope, or pocket
  3. a blow dealt with a flat object; slap
  4. a movable surface fixed to the trailing edge of an aircraft wing that increases lift during takeoff and drag during landing
  5. surgery a piece of tissue partially connected to the body, either following an amputation or to be used as a graft
  6. informal a state of panic, distress, or agitation
  7. phonetics an (r) produced by allowing the tongue to give a single light tap against the alveolar ridge or uvula

Word Origin for flap

C14: probably of imitative origin
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for flapping



early 14c., "dash about, shake;" later "strike, hit;" see flap (n.). Meaning "to swing loosely" is from 1520s. Related: Flapped; flapping.



mid-14c., flappe "a blow, slap," probably imitative of the sound of striking. Meaning "something that hangs down" is first recorded 1520s. Sense of "motion or noise like a bird's wing" is 1774; meaning "disturbance, noisy tumult" is 1916, British slang.

Online Etymology Dictionary, © 2010 Douglas Harper

flapping in Medicine


  1. Tissue used in surgical grafting that is only partially detached from its donor site so that it continues to be nourished during transfer to the recipient site.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.