old vs stale

old is a noun but stale is not a noun.

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

old (noun)	stale (noun)
past times

old (adjective)	stale (adjective)
of long duration; not new	lacking freshness, palatability, or showing deterioration from age
(used especially of persons) having lived for a relatively long time or attained a specific age	lacking originality or spontaneity; no longer new
skilled through long experience
(used for emphasis) very familiar
excellent
just preceding something else in time or order
belonging to some prior time

old (verb)	stale (verb)
	urinate, of cattle and horses