palpitate vs flutter

palpitate is not a noun while flutter is a noun.

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

As verbs, palpitate and flutter are synonyms defined as:

palpitate (noun)	flutter (noun)
	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

palpitate (verb)	flutter (verb)
beat rapidly	wink briefly
shake with fast, tremulous movements	beat rapidly
cause to throb or 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