trembling vs palpitation

trembling and palpitation both are nouns.

Word	Noun	Adjective	Verb	Adverb
trembling	Yes	Yes	No	No
palpitation	Yes	No	No	No

As nouns, trembling and palpitation are synonyms defined as:

Other synonyms of trembling include quiver, quivering, shakiness, shaking, vibration.

trembling (noun)	palpitation (noun)
a shaky motion	a rapid and irregular heart beat
	a shaky motion

trembling (adjective)	palpitation (adjective)
vibrating slightly and irregularly; as e.g. with fear or cold or like the leaves of an aspen in a breeze