overage vs old

overage and old both are nouns.

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

overage (noun)	old (noun)
a surplus or excess of money or merchandise that is actually on hand and that exceeds expectations	past times

overage (adjective)	old (adjective)
too old to be useful	of long duration; not new
	(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