counterfeit vs spurious

counterfeit is a noun but spurious is not a noun.

Word	Noun	Adjective	Verb	Adverb
counterfeit	Yes	Yes	Yes	No
spurious	No	Yes	No	No

counterfeit (noun)	spurious (noun)
a copy that is represented as the original

counterfeit (adjective)	spurious (adjective)
not genuine; imitating something superior	false or fake; not what it appears to be
	plausible but false
	born out of wedlock
	ostensibly valid, but not actually valid

counterfeit (verb)	spurious (verb)
make a copy of with the intent to deceive