Russian vs indigen

Russian and indigen both are nouns.

Word	Noun	Adjective	Verb	Adverb
Russian	Yes	Yes	No	No
indigen	Yes	No	No	No

As nouns, indigen is a hypernym of Russian; that is, indigen is a word with a broader meaning than Russian:

Other hypernyms of Russian include aboriginal, aborigine, indigene, native.

Russian (noun)	indigen (noun)
the Slavic language that is the official language of Russia	an indigenous person who was born in a particular place
a native or inhabitant of Russia

Russian (adjective)	indigen (adjective)
of or pertaining to or characteristic of Russia or its people or culture or language