Athabascan vs Chipewyan

Athabascan and Chipewyan both are nouns.

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

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

As nouns, Chipewyan is a hyponym of Athabascan; that is, Chipewyan 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
Chipewyan: a member of the Athapaskan people living in western Canada between Great Slave Lake and Hudson Bay

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

Athabascan (noun)	Chipewyan (noun)
a group of Amerindian languages (the name coined by an American anthropologist, Edward Sapir)	the language spoken by the Chipewyan
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 the Athapaskan people living in western Canada between Great Slave Lake and Hudson Bay