tremble vs palpitate

tremble is a noun but palpitate is not a noun.

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

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

Other hyponyms of tremble include shiver, shudder, thrill, throb, quake, quiver.

tremble (noun)	palpitate (noun)
a reflex motion caused by cold or fear or excitement

tremble (verb)	palpitate (verb)
move or jerk quickly and involuntarily up and down or sideways	beat rapidly
	shake with fast, tremulous movements
	cause to throb or beat rapidly