coffee substitute vs coffee

coffee substitute and coffee both are nouns.

Word	Noun	Adjective	Verb	Adverb
coffee substitute	Yes	No	No	No
coffee	Yes	No	No	No

As nouns, coffee is a hypernym of coffee substitute; that is, coffee is a word with a broader meaning than coffee substitute:

coffee substitute: a drink resembling coffee that is sometimes substituted for it
coffee: a beverage consisting of an infusion of ground coffee beans

Other hypernyms of coffee substitute include java.

coffee substitute (noun)	coffee (noun)
a drink resembling coffee that is sometimes substituted for it	a medium brown to dark-brown color
	a beverage consisting of an infusion of ground coffee beans
	a seed of the coffee tree; ground to make coffee
	any of several small trees and shrubs native to the tropical Old World yielding coffee beans