Italian vs Italian Republic

Italian and Italian Republic both are nouns.

Word	Noun	Adjective	Verb	Adverb
Italian	Yes	Yes	No	No
Italian Republic	Yes	No	No	No

Italian (noun)	Italian Republic (noun)
the Romance language spoken in Italy	a republic in southern Europe on the Italian Peninsula; was the core of the Roman Republic and the Roman Empire between the 4th century BC and the 5th century AD
a native or inhabitant of Italy

Italian (adjective)	Italian Republic (adjective)
of or pertaining to or characteristic of Italy or its people or culture or language