Worship of Satan (usually synonymous with "the Devil").
Religious groups that follow Satanism include Luciferians and Laveyans.
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.
LaVeyan Satanism.
A devilish disposition.