flutter vs flap

flutter and flap both are nouns.

Word	Noun	Adjective	Verb	Adverb
flutter	Yes	No	Yes	No
flap	Yes	No	Yes	No

As nouns, flutter and flap are synonyms defined as:

Other synonyms of flutter include flapping, fluttering.

As verbs, flap is a hypernym of flutter; that is, flap is a word with a broader meaning than flutter:

Other hypernyms of flutter include beat.

flutter (noun)	flap (noun)
the act of moving back and forth	any broad thin and limber covering attached at one edge; hangs loose or projects freely
the motion made by flapping up and down	a movable airfoil that is part of an aircraft wing; used to increase lift or drag
abnormally rapid beating of the auricles of the heart (especially in a regular rhythm); can result in heart block	a movable piece of tissue partly connected to the body
a disorderly outburst or tumult	the motion made by flapping up and down
	an excited state of agitation

flutter (verb)	flap (verb)
wink briefly	pronounce with a flap, of alveolar sounds
beat rapidly	make a fuss; be agitated
move back and forth very rapidly	to flutter noisily when moved by the wind
move along rapidly and lightly; skim or dart	move in a wavy pattern or with a rising and falling motion
flap the wings rapidly or fly with flapping movements	move with a flapping motion
	move with a thrashing motion