milk vs body fluid

milk and body fluid both are nouns.

Word	Noun	Adjective	Verb	Adverb
milk	Yes	No	Yes	No
body fluid	Yes	No	No	No

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

milk (noun)	body fluid (noun)
produced by mammary glands of female mammals for feeding their young	the liquid parts of the body
a white nutritious liquid secreted by mammals and used as food by human beings
any of several nutritive milklike liquids

milk (verb)	body fluid (verb)
take milk from female mammals
add milk to
exploit as much as possible