demon vs incubus

demon and incubus both are nouns.

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

As nouns, incubus is a hyponym of demon; that is, incubus is a word with a more specific, narrower meaning than demon:

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

Other hyponyms of demon include succuba, succubus, dibbuk, dybbuk.

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