forgery vs imitation

forgery and imitation both are nouns.

Word	Noun	Adjective	Verb	Adverb
forgery	Yes	No	No	No
imitation	Yes	Yes	No	No

As nouns, imitation is a hypernym of forgery; that is, imitation is a word with a broader meaning than forgery:

forgery (noun)	imitation (noun)
criminal falsification by making or altering an instrument with intent to defraud	copying (or trying to copy) the actions of someone else
a copy that is represented as the original	something copied or derived from an original
	the doctrine that representations of nature or human behavior should be accurate imitations
	a representation of a person that is exaggerated for comic effect

forgery (adjective)	imitation (adjective)
	not genuine or real; being an imitation of the genuine article