Republic of India vs Indian

Republic of India and Indian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Republic of India	Yes	No	No	No
Indian	Yes	Yes	No	No

Republic of India (noun)	Indian (noun)
a republic in the Asian subcontinent in southern Asia; second most populous country in the world; achieved independence from the United Kingdom in 1947	any of the languages spoken by Amerindians
	a native or inhabitant of India

Republic of India (adjective)	Indian (adjective)
	of or relating to or characteristic of India or the East Indies or their peoples or languages or cultures
	of or pertaining to Native Americans or their culture or languages