river vs Cimarron

river and Cimarron both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Cimarron	Yes	No	No	No

river (noun)	Cimarron (noun)
a large natural stream of water (larger than a creek)	a river that rises in northeastern New Mexico and flows eastward into Oklahoma where it becomes a tributary of the Arkansas River