IPA: /dɪˈmoʊ.ni.ɑ.kəl/
KK: /dɪˈmoʊniˌɑkəl/
Relating to or resembling a demon; having qualities that are evil or wicked.
The movie featured a demoniacal character who caused chaos and fear.
Demoniacal → It is formed from "daemon" (from Greek "daimon", meaning spirit or divine power) and the suffix "-iacal" (meaning relating to). The word "demoniacal" refers to something that is related to or characteristic of a demon or evil spirit.
Think of the Greek word for spirit ('daemon') to remember that 'demoniacal' relates to something that is like a demon or evil spirit.