Greed denotes desire to acquire wealth or possessions beyond the needs of the individual, especially when this accumulation of possession denies others legitimate needs or access to those or other resources. For example, amassing a large collection of seashells would not be considered greed, unless in doing so, the needs of others were jeopardized. Essential to the concept of greed is the awareness that the needs of others are denied, thus rivalrous goods exemplify greed while non-rivalrous goods may not. Greed also often involves using wealth to gain power over others, sometimes by denying wealth or power.

Some desire to increase one's wealth is nearly universal and acceptable in any culture, but this simple want is not considered greed. Greed is the extreme form of this desire, especially where one desires things simply for the sake of owning them (such as the desire to have great amounts of money not to purchase objects, but possession or the money is an end in itself). Greed typically entails acquiring material possessions at the expense of other person's welfare (for example, a father buying himself a new car rather than fix the roof of his family's home) or otherwise reflect priorities.

Coveting another person's goods is usually called envy, a word commonly confused with jealousy. The two words denote opposite forms of greed. We may envy and wish to have the possessions or qualities of another, but we jealously guard the possessions or qualities we believe we have and refuse to share these with others.

Greed for food or drink, combined with excessive indulgence in them, is called gluttony. Excessive greed for and indulgence in sex is called lust, although this term no longer carries as negative connotations as it once did.

A woodcut by Ugo da Carpi, is entitled "Hercules Chasing Avarice from the Temple of the Muses."^[1] Thomas Aquinas metaphorically described the sin of Avarice as "Mammon being carried up from Hell by a wolf, coming to inflame the human heart with Greed".

Proponents of laissez-faire capitalism sometimes argue that greed should not be considered a negative trait and should instead be embraced, as they claim that greed is a profoundly benevolent force in human affairs, as well as a necessary foundation for the capitalist system. Critics have argued this definition confuses greed with self-interest, which can be benign.

greed kills.