body of water vs river

body of water and river both are nouns.

Word	Noun	Adjective	Verb	Adverb
body of water	Yes	No	No	No
river	Yes	No	No	No

body of water (noun)	river (noun)
the part of the earth's surface covered with water (such as a river or lake or ocean)	a large natural stream of water (larger than a creek)