Buddhism employs the all-inclusive term klesha to mean the mistaken thoughts and actions that obstruct our attainment of enlightenment. (Kleshas are also thought of as impurities, and eliminating them is described as purifying the mind.) The most fundamental of these obstructions are the three poisons: greed, anger, and foolishness. Greed is desire for and attachment to things regarded as pleasant and enjoyable, and anger is aversion and resistance to things regarded as unpleasant and undesirable. Greed and anger are the same as craving, since craving is a mistaken desire, a mistaken love or hate of things. Foolishness, a lack of knowledge of the truth, is identical with ignorance in the Twelve-linked Chain of Dependent Origination. The three poisons, then, can be reduced to craving and ignorance, the fundamental causes of all suffering.
Basic Buddhist Concepts