Amerindian vs Native American

Amerindian and Native American both are nouns.

Word	Noun	Adjective	Verb	Adverb
Amerindian	Yes	No	No	No
Native American	Yes	Yes	No	No

As nouns, Amerindian and Native American are synonyms defined as:

Amerindian and Native American: any member of the peoples living in North or South America before the Europeans arrived

Amerindian (noun)	Native American (noun)
any member of the peoples living in North or South America before the Europeans arrived	any member of the peoples living in North or South America before the Europeans arrived

Amerindian (adjective)	Native American (adjective)
	of or pertaining to Native Americans or their culture or languages