body fluid vs liquid body substance

body fluid and liquid body substance both are nouns.

Word	Noun	Adjective	Verb	Adverb
body fluid	Yes	No	No	No
liquid body substance	Yes	No	No	No

As nouns, body fluid and liquid body substance are synonyms defined as:

Other synonyms of body fluid include bodily fluid, humor, humour.

body fluid (noun)	liquid body substance (noun)
the liquid parts of the body	the liquid parts of the body