Definition of demonianism in US English:

demonianism

noun

  • The fact or condition of being (supposedly) possessed by a demon.

Origin

Mid 18th century; earliest use found in William Warburton (1698–1779), bishop of Gloucester and religious controversialist. From demonian + -ism.

Pronunciation

demonianism

/dɪˈməʊnɪənɪz(ə)m/