DEMONIAC or DEMONIACAL or DEMONIAN, adjective 1. Pertaining to demons or evil spirits. 2. Influenced by demons; produced by demons or evil spirits. DEMONIAC phrensy. DEMONIAC, noun A human being possessed by a demon; one whose volition and other mental faculties are overpowered, restrained, or disturbed, in their regular operation, by an evil spirit, or by a created spiritual being of superior power.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI