smashing vs neat

smashing is a noun but neat is not a noun.

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

As adjectives, smashing and neat are synonyms defined as:

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

smashing (noun)	neat (noun)
the act of breaking something into small pieces

smashing (adjective)	neat (adjective)
excellent	free from clumsiness; precisely or deftly executed
	excellent
	superficially impressive, but lacking depth and attention to the true complexities of a subject
	clean or organized
	(of an alcoholic drink) without water
	showing care in execution