Klamath vs Klamath River

Klamath and Klamath River both are nouns.

Word	Noun	Adjective	Verb	Adverb
Klamath	Yes	No	No	No
Klamath River	Yes	No	No	No

As nouns, Klamath and Klamath River are synonyms defined as:

Klamath and Klamath River: a river flowing southwest from Oregon through northern California to the Pacific Ocean

Klamath (noun)	Klamath River (noun)
a river flowing southwest from Oregon through northern California to the Pacific Ocean	a river flowing southwest from Oregon through northern California to the Pacific Ocean