body of water vs briny

body of water and briny both are nouns.

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

As nouns, briny is a hyponym of body of water; that is, briny is a word with a more specific, narrower meaning than body of water:

body of water: the part of the earth's surface covered with water (such as a river or lake or ocean)
briny: any very large body of (salt) water

body of water (noun)	briny (noun)
the part of the earth's surface covered with water (such as a river or lake or ocean)	any very large body of (salt) water

body of water (adjective)	briny (adjective)
	slightly salty (especially from containing a mixture of seawater and fresh water)