jauntiness vs last word

jauntiness and last word both are nouns.

Word	Noun	Adjective	Verb	Adverb
jauntiness	Yes	No	No	No
last word	Yes	No	No	No

As nouns, last word is a hypernym of jauntiness; that is, last word is a word with a broader meaning than jauntiness:

Other hypernyms of jauntiness include chic, chichi, chicness, modishness, smartness, stylishness, swank.

jauntiness (noun)	last word (noun)
stylishness as evidenced by a smart appearance	elegance by virtue of being fashionable
a breezy liveliness	the final statement in a verbal argument
	an authoritative statement