Anhedonia: Loss of the capacity to experience pleasure. The inability to gain pleasure from normally pleasurable experiences. Anhedonia is a core clinical feature of depression, schizophrenia, and some other mental illnesses.
"Anhedonia" is derived from the Greek "a-" (without) "hedone" (pleasure, delight). Other words derived from "hedone" include hedonism (a philosophy that emphasizes pleasure as the main aim of life), hedonist (a pleasure-seeker), and hedonophobia (an excessive and persistent fear of pleasure).