piquancy vs spiciness

piquancy and spiciness both are nouns.

Word	Noun	Adjective	Verb	Adverb
piquancy	Yes	No	No	No
spiciness	Yes	No	No	No

As nouns, spiciness is a hypernym of piquancy; that is, spiciness is a word with a broader meaning than piquancy:

Other hypernyms of piquancy include spice, spicery.

piquancy (noun)	spiciness (noun)
a tart spicy quality	the property of being seasoned with spice and so highly flavored
the quality of being agreeably stimulating or mentally exciting	behavior or language bordering on indelicacy