piquant vs savoury

piquant is not a noun while savoury is a noun.

Word	Noun	Adjective	Verb	Adverb
piquant	No	Yes	No	No
savoury	Yes	Yes	No	No

As adjectives, piquant and savoury are synonyms defined as:

Other synonyms of piquant include savory, zesty.

piquant (noun)	savoury (noun)
	either of two aromatic herbs of the mint family
	an aromatic or spicy dish served at the end of dinner or as an hors d'oeuvre

piquant (adjective)	savoury (adjective)
attracting or delighting	morally wholesome or acceptable
engagingly stimulating or provocative	having a pleasant taste
having an agreeably pungent taste	having an agreeably pungent taste