duplicate vs copy

duplicate and copy both are nouns.

Word	Noun	Adjective	Verb	Adverb
duplicate	Yes	Yes	Yes	No
copy	Yes	No	Yes	No

As nouns, copy is a hypernym of duplicate; that is, copy is a word with a broader meaning than duplicate:

As verbs, copy is a hyponym of duplicate; that is, copy is a word with a more specific, narrower meaning than duplicate:

Other hyponyms of duplicate include replicate, recapitulate, geminate, reduplicate.

duplicate (noun)	copy (noun)
a copy that corresponds to an original exactly	a thing made to be similar or identical to another thing
something additional of the same kind	a reproduction of a written record (e.g. of a legal or school record)
	matter to be printed; exclusive of graphical materials
	material suitable for a journalistic account

duplicate (adjective)	copy (adjective)
being two identical
identically copied from an original

duplicate (verb)	copy (verb)
increase twofold	reproduce someone's behavior or looks
make or do or perform again	make a replica of
make a duplicate or duplicates of	reproduce or make an exact copy of
duplicate or match	copy down as is