Indian vs Republic of India

Indian and Republic of India both are nouns.

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

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

Indian (adjective)	Republic of India (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