1. Pertaining to, or characteristic of, a demon or evil spirit; devilish; as, a demoniac being; demoniacal practices. Sarcastic, demoniacal laughter. Thackeray.

2. Influenced or produced by a demon or evil spirit; as, demoniac or demoniacal power. "Demoniac frenzy." Milton.

DEMONIAC
De*mo"ni*ac, n.

1. A human being possessed by a demon or evil spirit; one whose faculties are directly controlled by a demon. The demoniac in the gospel was sometimes cast into the fire. Bates.

2. (Eccl. Hist.)

Defn: One of a sect of Anabaptists who maintain that the demons or devils will finally be saved.

DEMONIACALLY
Dem`o*ni"a*cal*ly, adv.

Defn: In a demoniacal manner.

DEMONIACISM
Dem`o*ni"a*cism, n.

Defn: The state of being demoniac, or the practices of demoniacs.