rusty vs old

rusty is not a noun while old is a noun.

Word	Noun	Adjective	Verb	Adverb
rusty	No	Yes	No	No
old	Yes	Yes	No	No

rusty (noun)	old (noun)
	past times

rusty (adjective)	old (adjective)
of the brown color of rust	of long duration; not new
ancient	(used especially of persons) having lived for a relatively long time or attained a specific age
covered with or consisting of rust	skilled through long experience
impaired in skill by neglect	(used for emphasis) very familiar
	excellent
	just preceding something else in time or order
	belonging to some prior time