item vs component part

item and component part both are nouns.

Word	Noun	Adjective	Verb	Adverb
item	Yes	No	No	Yes
component part	Yes	No	No	No

As nouns, component part is a hypernym of item; that is, component part is a word with a broader meaning than item:

item: a distinct part that can be specified separately in a group of things that could be enumerated on a list
component part: something determined in relation to something that includes it

Other hypernyms of item include component, constituent, part, portion.

As nouns, component part is a hypernym of item; that is, component part is a word with a broader meaning than item:

item: a small part that can be considered separately from the whole
component part: something determined in relation to something that includes it

Other hypernyms of item include component, constituent, part, portion.

item (noun)	component part (noun)
a whole individual unit; especially when included in a list or collection	something determined in relation to something that includes it
an isolated fact that is considered separately from the whole
a distinct part that can be specified separately in a group of things that could be enumerated on a list
an individual instance of a type of symbol
a small part that can be considered separately from the whole

item (adverb)	component part (adverb)
(used when listing or enumerating items) also