Envy (also called invidiousness) may be defined as an emotion that "occurs when a person lacks another's superior quality, achievement, or possession and either desires it or wishes that the other lacked it."Elster, J. (1991). Envy in social life. In R. J. Zeckhauser (Ed.), Strategy and choices(pp. 49-82). Cambridge, MA: MIT Press.

Bertrand Russell said envy was one of the most potent causes of unhappiness. It is a universal and most unfortunate aspect of human nature because not only is the envious person rendered unhappy by his envy, but also wishes to inflict misfortune on others.

Although envy is generally seen as something negative, Russell(1930, p. 90-91)also believed that envy was a driving force behind the movement towards democracy and must be endured in order to achieve a more just social system.

Envy and jealousy

The words "Envy" and "Jealousy" are often used interchangeably, but in correct usage, both words stand for two different distinct emotions. In proper usage, jealousy is the fear of losing something that one possesses to another person (a loved one in the prototypical form), while envy is the pain or frustration caused by another person having something that one does not have oneself. Envy typically involves two people, and jealousy typically involves three people. Envy and jealousy result from different situations and are distinct emotional experiences.

Both envy and jealousy are related to schadenfreude, the rejoicing at, or taking joy in, or getting pleasure from the misfortunes of others.

Envy in philosophy

Aristotle (in Rhetoric) defined envy (phthonos) "as the pain caused by the good fortune of others", while Kant defined it as "a reluctance to see our own well-being overshadowed by another's because the standard we use to see how well off we are is not the intrinsic worth of our own well-being but how it compares with that of others" (in Metaphysics of Morals).

Envy in the arts

In some cultures, envy is often associated with the color green, as in "green with envy". The phrase "green-eyed monster" refers to an individual whose current actions appear motivated by envy. This is based on a line from Shakespeare's Othello. Shakespeare mentions it also in The Merchant of Venice when Portia states: "How all the other passions fleet to air, as doubtful thoughts and rash embraced despair and shuddering fear and green-eyed jealousy!" Envy is known as one of the most powerful human emotions for its ability to control one as if envy was an entity in itself. Countless men and women have fallen prey to brief periods of intense envy followed by anger which then translates into aggression. One of the most common examples is a pair of lovers in which a secret love is discovered and can lead to sorrow, then intense envy, and eventually anger and aggression.