low-fat milk vs milk

low-fat milk and milk both are nouns.

Word	Noun	Adjective	Verb	Adverb
low-fat milk	Yes	No	No	No
milk	Yes	No	Yes	No

As nouns, milk is a hypernym of low-fat milk; that is, milk is a word with a broader meaning than low-fat milk:

low-fat milk: milk which has had its fat content reduced
milk: a white nutritious liquid secreted by mammals and used as food by human beings

low-fat milk (noun)	milk (noun)
milk which has had its fat content reduced	produced by mammary glands of female mammals for feeding their young
	a white nutritious liquid secreted by mammals and used as food by human beings
	any of several nutritive milklike liquids

low-fat milk (verb)	milk (verb)
	take milk from female mammals
	add milk to
	exploit as much as possible