copy vs duplicate

copy and duplicate both are nouns.

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

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

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

Other hypernyms of copy include double, reduplicate, repeat, replicate.

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

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

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