flutter vs flapping

flutter and flapping both are nouns.

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

As nouns, flutter and flapping are synonyms defined as:

Other synonyms of flutter include flap, fluttering.

flutter (noun)	flapping (noun)
the act of moving back and forth	the motion made by flapping up and down
the motion made by flapping up and down
abnormally rapid beating of the auricles of the heart (especially in a regular rhythm); can result in heart block
a disorderly outburst or tumult

flutter (verb)	flapping (verb)
wink briefly
beat rapidly
move back and forth very rapidly
move along rapidly and lightly; skim or dart
flap the wings rapidly or fly with flapping movements