Definition of demonomaniac in English:

demonomaniac

noun

historical
  • A person thought to be possessed by an evil spirit; specifically a person who believes this of himself or herself; a person affected with demonomania.

Origin

Mid 19th century; earliest use found in Thomas Cooper. From demono- + -maniac, after French démonomaniaque.

Pronunciation

demonomaniac

/ˌdiːmənə(ʊ)ˈmeɪnɪak/