neat vs old

neat is not a noun while old is a noun.

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

As adjectives, neat and old are synonyms defined as:

Other synonyms of neat include bang-up, bully, corking, cracking, dandy, great, groovy, keen, nifty, not bad, peachy, slap-up, smashing, swell.

neat (noun)	old (noun)
	past times

neat (adjective)	old (adjective)
free from clumsiness; precisely or deftly executed	of long duration; not new
excellent	(used especially of persons) having lived for a relatively long time or attained a specific age
superficially impressive, but lacking depth and attention to the true complexities of a subject	skilled through long experience
clean or organized	(used for emphasis) very familiar
(of an alcoholic drink) without water	excellent
showing care in execution	just preceding something else in time or order
	belonging to some prior time