Athabascan vs Navajo

Athabascan and Navajo both are nouns.

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

As nouns, Navajo is a hyponym of Athabascan; that is, Navajo 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)
Navajo: the Athapaskan language spoken by the Navaho

As nouns, Navajo is a hyponym of Athabascan; that is, Navajo 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
Navajo: a member of an Athapaskan people that migrated to Arizona and New Mexico and Utah

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

Athabascan (noun)	Navajo (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