A belief in and reverence for devils (especially Satan) WordNet 3.0 & Open English WordNet

Satanism is a group of ideological and philosophical beliefs based on Satan. Wikipedia

Belief or social phenomenon that features the veneration or admiration of Satan or a similar figure. Wikipedia Disambiguation

Group of ideological and philosophical beliefs based on Satan Wikidata

A profession, philosophy, or ideological construct featuring a positive, admirable, or useful association to the figure, character or entity known as 'Satan'; or, featuring opposition to all morality and the procurement of what is wanted regardless of the consequences concerning others. Wiktionary

Belief in, or worship of demons or devils. Wiktionary

The property of having attributes that are demonic or Satanic. Wiktionary