One of the mysteries of the English language finally explained.
Synonyms of flap in English:
flap
See definition of flap
verb
1‘the mallards flapped their wings angrily’
beat, flutter, move up and down, agitate, wave, wag, waggle, shake, swing, twitch
thresh, thrash, flail
vibrate, quiver, tremble, oscillate
2‘his shirt tails flapped in the breeze’
flutter, swing, sway, ripple, undulate, stir, shake, quiver, shiver, tremble, fly, blow
3‘it was a deliberate ploy to make us flap’
panic, go into a panic, become flustered, be agitated, fuss
press the panic button, be in a state, be in a tizzy, be in a dither, be in a twitter
noun
1‘large pockets with buttoned flaps’
fold, overhang, overlap, covering
lappet, lap, tab
2‘the surviving bird made a few final despairing flaps’
flutter, fluttering, beat, beating, waving, shaking, flailing
3‘I'm in a frightful flap about leaving’
panic, fluster, state of agitation, state of panic
informal state, dither, twitter, blue funk, stew, tizz, tizzy, tiz-woz
North American informal twit
4‘she created a flap when she came out with her controversial statement’
fuss, agitation, commotion, stir, hubbub, excitement, tumult, ado, storm, uproar, flurry
controversy, to-do, palaver, brouhaha, furore
ballyhoo, hoopla, hoo-ha, song and dance
British carry-on, kerfuffle