trembling vs shaking

trembling and shaking both are nouns.

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

As nouns, trembling and shaking are synonyms defined as:

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

trembling (noun)	shaking (noun)
a shaky motion	the act of causing something to move up and down (or back and forth) with quick movements
	a shaky motion

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