Irrawaddy River vs Irrawaddy

Irrawaddy River and Irrawaddy both are nouns.

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

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

Irrawaddy River and Irrawaddy: the main river of Myanmar rising in the north and flowing south through the length of Burma to empty into the Andaman Sea

Irrawaddy River (noun)	Irrawaddy (noun)
the main river of Myanmar rising in the north and flowing south through the length of Burma to empty into the Andaman Sea	the main river of Myanmar rising in the north and flowing south through the length of Burma to empty into the Andaman Sea