shakiness vs trembling

shakiness and trembling both are nouns.

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

As nouns, shakiness and trembling are synonyms defined as:

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

shakiness (noun)	trembling (noun)
the quality of being unstable and insecure	a shaky motion
a shaky motion

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