archaic vs old

archaic is not a noun while old is a noun.

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

archaic (noun)	old (noun)
	past times

archaic (adjective)	old (adjective)
little evolved from or characteristic of an earlier ancestral type	of long duration; not new
so extremely old as seeming to belong to an earlier period	(used especially of persons) having lived for a relatively long time or attained a specific age
	skilled through long experience
	(used for emphasis) very familiar
	excellent
	just preceding something else in time or order
	belonging to some prior time