Athabascan vs Navaho

Athabascan and Navaho both are nouns.

Word	Noun	Adjective	Verb	Adverb
Athabascan	Yes	No	No	No
Navaho	Yes	No	No	No

As nouns, Navaho is a hyponym of Athabascan; that is, Navaho is a word with a more specific, narrower meaning than Athabascan:

Athabascan: a group of Amerindian languages (the name coined by an American anthropologist, Edward Sapir)
Navaho: the Athapaskan language spoken by the Navaho

As nouns, Navaho is a hyponym of Athabascan; that is, Navaho is a word with a more specific, narrower meaning than Athabascan:

Athabascan: a member of any of the North American Indian groups speaking an Athapaskan language and living in the subarctic regions of western Canada and central Alaska
Navaho: a member of an Athapaskan people that migrated to Arizona and New Mexico and Utah

Other hyponyms of Athabascan include Apache, Chipewyan, Hupa, Mattole, Navajo.

Athabascan (noun)	Navaho (noun)
a group of Amerindian languages (the name coined by an American anthropologist, Edward Sapir)	the Athapaskan language spoken by the Navaho
a member of any of the North American Indian groups speaking an Athapaskan language and living in the subarctic regions of western Canada and central Alaska	a member of an Athapaskan people that migrated to Arizona and New Mexico and Utah