blink vs flutter

blink and flutter both are nouns.

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

As verbs, flutter is a hyponym of blink; that is, flutter is a word with a more specific, narrower meaning than blink:

Other hyponyms of blink include palpebrate, bat.

blink (noun)	flutter (noun)
a reflex that closes and opens the eyes rapidly	the act of moving back and forth
	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

blink (verb)	flutter (verb)
briefly shut the eyes	wink briefly
keep back by blinking	beat rapidly
gleam or glow intermittently	move back and forth very rapidly
	move along rapidly and lightly; skim or dart
	flap the wings rapidly or fly with flapping movements