river vs Parnaiba

river and Parnaiba both are nouns.

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

river (noun)	Parnaiba (noun)
a large natural stream of water (larger than a creek)	a river in northeastern Brazil that flows generally northward to the Atlantic Ocean