Indian vs Amerindic

Indian is a noun but Amerindic is not a noun.

Word	Noun	Adjective	Verb	Adverb
Indian	Yes	Yes	No	No
Amerindic	No	Yes	No	No

As adjectives, Indian and Amerindic are synonyms defined as:

Indian and Amerindic: of or pertaining to Native Americans or their culture or languages

Other synonyms of Indian include Amerind, Native American.

Indian (noun)	Amerindic (noun)
any of the languages spoken by Amerindians
a native or inhabitant of India

Indian (adjective)	Amerindic (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
of or pertaining to Native Americans or their culture or languages