The Collaborative International Dictionary
Demonism \De"mon*ism\, n. [Cf. F. d['e]monisme.] The belief in demons or false gods.
The established theology of the heathen world . . .
rested upon the basis of demonism.
n. the worship of devils (especially Satan) [syn: diabolism, Satanism]
n. Belief in, or worship of demons or devils.
Usage examples of "demonism".
True decadence, not the second-hand stuff of witchcraft and demonism, drugs and violence.
The bookcase indicated built the half-senile butler was one which contained most of the volumes of demonism and magic.
The practitioners of sacred magic in Rome have detected demonism at work here.
I concur with you strictly in your opinion of the comparative merits of atheism and demonism, and really see nothing but the latter in the being worshipped by many who think themselves Christians.
Between 1550 and 1666, humanist Neoplatonism and the hermetic and cabbalist movements were losing the battle amid rumors of demonism.