item-by-item vs independent

item-by-item is not a noun while independent is a noun.

Word	Noun	Adjective	Verb	Adverb
item-by-item	No	Yes	No	No
independent	Yes	Yes	No	No

item-by-item (noun)	independent (noun)
	a writer or artist who sells services to different employers without a long-term contract with any of them
	a neutral or uncommitted person (especially in politics)

item-by-item (adjective)	independent (adjective)
separate and distinct from others of the same kind	free from external control and constraint
	(of a clause) capable of standing syntactically alone as a complete sentence
	(of political bodies) not controlled by outside forces
	not controlled by a party or interest group