gulf vs body of water

gulf and body of water both are nouns.

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

As nouns, body of water is a hypernym of gulf; that is, body of water is a word with a broader meaning than gulf:

gulf: an arm of a sea or ocean partly enclosed by land; larger than a bay
body of water: the part of the earth's surface covered with water (such as a river or lake or ocean)

Other hypernyms of gulf include water.

gulf (noun)	body of water (noun)
an unbridgeable disparity (as from a failure of understanding)	the part of the earth's surface covered with water (such as a river or lake or ocean)
a deep wide chasm
an arm of a sea or ocean partly enclosed by land; larger than a bay