Lust is one of the Seven Deadly Sins. It is a psychological force producing intense desire for an object, or circumstance while already having a significant amount of the desired object. All demons who offer love are considered demons of lust.
Lust can take any form such as the lust for sexuality, money, or power. It can take such mundane forms as the lust for food as distinct from the need for food or lust for redolence, when one is lusting for a particular smell that brings back memories. It is similar to but distinguished from passion, in that passion propels individuals to achieve benevolent goals whilst lust does not.
Lust is defined as immoral because its object or action of affection is improperly ordered according to natural law and/or the appetite for the particular object (eg sexual desire) is governing the person's intellect and will rather than the intellect and will governing the appetite for that object.