Namoi River vs Namoi

Namoi River and Namoi both are nouns.

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

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

Namoi River and Namoi: a river in southeastern Australia that flows generally northwest to join the Darling River

Namoi River (noun)	Namoi (noun)
a river in southeastern Australia that flows generally northwest to join the Darling River	a river in southeastern Australia that flows generally northwest to join the Darling River