last word vs modishness

last word and modishness both are nouns.

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

As nouns, last word and modishness are synonyms defined as:

Other synonyms of last word include chic, chichi, chicness, smartness, stylishness, swank.

last word (noun)	modishness (noun)
elegance by virtue of being fashionable	elegance by virtue of being fashionable
the final statement in a verbal argument
an authoritative statement