evil

thumb|In many Abrahamic religions, demons are considered to be evil beings and are contrasted with angels, who are their good contemporaries.|354x354px Evil, as a concept, is usually defined as profoundly immoral behavior, and it is related to acts that cause unnecessary pain and suffering to others.

Evil is commonly seen as the opposite, or sometimes absence, of good. It can be an extremely broad concept, although in everyday usage it is often more narrowly used to talk about profound wickedness and against common good. It is generally seen as taking multiple possible forms, such as the form of personal moral evil commonly associated with the word, or impersonal natural evil (as in the case of natural disasters or illnesses), and in religious thought, the form of the demonic or supernatural/eternal. While some religions, world views, and philosophies focus on "good versus evil", others deny evil's existence and usefulness in describing people.