sassy vs smart

sassy is not a noun while smart is a noun.

Word	Noun	Adjective	Verb	Adverb
sassy	No	Yes	No	No
smart	Yes	Yes	Yes	No

As adjectives, sassy and smart are synonyms defined as:

Other synonyms of sassy include fresh, impertinent, impudent, overbold, saucy, wise.

sassy (noun)	smart (noun)
	a kind of pain such as that caused by a wound or a burn or a sore

sassy (adjective)	smart (adjective)
improperly forward or bold	showing mental alertness and calculation and resourcefulness
	capable of independent and apparently intelligent action
	quick and brisk
	improperly forward or bold
	characterized by quickness and ease in learning
	painfully severe
	elegant and stylish

sassy (verb)	smart (verb)
	be the source of pain