walnut oil vs oil

walnut oil and oil both are nouns.

Word	Noun	Adjective	Verb	Adverb
walnut oil	Yes	No	No	No
oil	Yes	No	Yes	No

As nouns, oil is a hypernym of walnut oil; that is, oil is a word with a broader meaning than walnut oil:

Other hypernyms of walnut oil include vegetable oil.

walnut oil (noun)	oil (noun)
oil from walnuts	oil paint containing pigment that is used by an artist
	any of a group of liquid edible fats that are obtained from plants
	a slippery or viscous liquid or liquefiable substance not miscible with water
	a dark oil consisting mainly of hydrocarbons

walnut oil (verb)	oil (verb)
	administer an oil or ointment to; often in a religious ceremony of blessing
	cover with oil, as if by rubbing