Hellenic Republic vs Greek

Hellenic Republic and Greek both are nouns.

Word	Noun	Adjective	Verb	Adverb
Hellenic Republic	Yes	No	No	No
Greek	Yes	Yes	No	No

Hellenic Republic (noun)	Greek (noun)
a republic in southeastern Europe on the southern part of the Balkan peninsula; known for grapes and olives and olive oil	the Hellenic branch of the Indo-European family of languages
	a native or inhabitant of Greece

Hellenic Republic (adjective)	Greek (adjective)
	of or relating to or characteristic of Greece or the Greeks or the Greek language