shaky vs trembling

shaky is not a noun while trembling is a noun.

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

As adjectives, shaky and trembling are synonyms defined as:

shaky and trembling: vibrating slightly and irregularly; as e.g. with fear or cold or like the leaves of an aspen in a breeze

Other synonyms of shaky include shivering.

shaky (noun)	trembling (noun)
	a shaky motion

shaky (adjective)	trembling (adjective)
not secure; beset with difficulties	vibrating slightly and irregularly; as e.g. with fear or cold or like the leaves of an aspen in a breeze
inclined to shake as from weakness or defect
vibrating slightly and irregularly; as e.g. with fear or cold or like the leaves of an aspen in a breeze