Darling River vs Darling

Darling River and Darling both are nouns.

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

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

Darling River and Darling: an Australian river; tributary of the Murray River

Darling River (noun)	Darling (noun)
an Australian river; tributary of the Murray River	an Australian river; tributary of the Murray River