incubus vs demon

incubus and demon both are nouns.

Word	Noun	Adjective	Verb	Adverb
incubus	Yes	No	No	No
demon	Yes	No	No	No

As nouns, demon is a hypernym of incubus; that is, demon is a word with a broader meaning than incubus:

incubus: a male demon believed to lie on sleeping persons and to have sexual intercourse with sleeping women
demon: an evil supernatural being

Other hypernyms of incubus include daemon, daimon, devil, fiend.

incubus (noun)	demon (noun)
a male demon believed to lie on sleeping persons and to have sexual intercourse with sleeping women	an evil supernatural being
someone who depresses or worries others	a cruel wicked and inhuman person
a situation resembling a terrifying dream	someone extremely diligent or skillful