Evil is a very old term for describing that which is morally bad, corrupt, wantonly destructive, selfish, and wicked. It is one half of the duality of good and evil expressed, in some form or another, by all known cultures. By its implication it describes a hierarchy of moral standards with regard to human behaviour; evil being the least desired, while love is the most praised. In a casual or derogatory use, the word "evil" can characterize people and behaviours that are painful, ruinous, or disastrous.
In longstanding religious traditions, "evil" is widely considered to be a mystery; that life and its rules are "governed" by an innate benevolence, and behaviour that directly contradicts "good nature" is not understandable in moral and reasoning terms. "Evil" characterises and describes aspects of human beings that deviate from the social, loving, righteous, natures within, which in contrast lead to social strength, and continuing survival, through love. In the forms of malice and selfishness, evil represents the socially-weakening and destructive behaviours that lead directly to a fruitless life and death.
Views on how good and evil are defined lie between two extremes. "Moral absolutism" holds that good and evil are fixed concepts established by God, nature, or some other authority. Moral relativism holds that standards of good and evil are only products of local culture, custom, or prejudice. Moral universalism is a recent humanist term to find a compromise between the unattainable absolutist sense of morality, and the unauthoritative relativist view.
Regardless of the source of their definitions, all human cultures have a set of "natural beliefs" about what things are evil. Natural evils generally include accidental death, disease, and other misfortunes. Moral evils generally include violence, deceit or other destructive behavior toward others, although the same behavior toward "outsiders" of the group may be considered "good." War provides many examples, and "God is always on the winning side." The Unification Church's definition of evil is: "Taking advantage of another person for one's own benefit."
The Abrahamic religions, as well as others, are largely centered around the concepts of good and evil, and this has lead to much religious debate. Many cultures and mythologies personify evil, such as with Satan in Christianity. Others describe evil spirits or demons as the inciters of acts.
Some sociologists, psychologists, psychiatrists and neuroscientists have attempted to construct scientific explanations for the development of specific characteristics of an "antisocial" personality type, called the sociopath. The sociopath is typified by extreme self-serving behavior, and a lack of conscience, or inability to empathize with others, to restrain self from, or to feel remorse for, harm personally caused to others. However, a diagnosis of anti-social or sociopath personality disorder (formerly called psychopathic mental disorder), is sometimes criticised as being, at the present time, no more scientific than calling a person evil. What critics perceive to be a moral determination is disguised, they argue, with a scientific-sounding name, but no complete description of a mechanism by which the abnormality can be identified is provided. In other words, critics argue, "sociopaths" are called such, because they are first thought to be "evil" - a determination which itself is not derived by a scientific method.
Many cultures recognize many levels of immoral behavior, from minor vices to major crimes. These beliefs are often encoded into the laws of a society, with methods of judgment and punishment for offenses.
As used by computer hackers, the jargon term evil implies that some system, program, person, or institution is sufficiently maldesigned as to be not worth the bother of dealing with. Unlike the adjectives in the cretinous/losing/brain-damaged series, evil does not imply incompetence or bad design, but rather a set of goals or design criteria fatally incompatible with the speaker's. This usage is more an esthetic and engineering judgment than a moral one in the mainstream sense. "We thought about adding a Blue Glue interface but decided it was too evil to deal with." "TECO is neat, but it can be pretty evil if you're prone to typos." Often pronounced with the first syllable lengthened, as /eeee'vil/. Compare evil and rude.