From Greek 'hēdonē' (pleasure), from PIE *sweh₂d- (sweet) — the same root behind English 'sweet' and Latin 'suāvis.'
A person who regards pleasure as the chief good and the proper aim of human life; one who pursues sensory pleasures as a way of life.
From 'hedonism' (coined in English c.1856) + the agent suffix '-ist.' 'Hedonism' was formed from Greek 'hēdonē' (ἡδονή), meaning pleasure, delight, or enjoyment, derived from 'hēdys' (ἡδύς), meaning sweet, pleasant, agreeable. Greek 'hēdys' traces to Proto-Indo-European *sweh₂d- (sweet, pleasant), one of the most recognisable roots across the family: it produced Latin 'suāvis' (sweet, pleasant — 'suave'), 'suādēre' (to urge sweetly — 'persuade,' 'dissuade'), Old English 'swēte' (sweet — English 'sweet'), Sanskrit 'svādu' (sweet, tasty), and Greek 'hēdys' via the regular *sw- → Greek h- shift. In Greek philosophy, 'hēdonē' became a technical term in ethics: the Cyrenaics (Aristippus, 4th c. BCE) made bodily pleasure the sole intrinsic good; Epicurus refined this to 'ataraxia' (tranquil pleasure, freedom from disturbance); the Stoics
The PIE root *sweh₂d- (sweet) that produced Greek 'hēdys' also produced English 'sweet' (through Germanic *swōtuz) and Latin 'suāvis' (sweet, agreeable, from which English gets 'suave'). A hedonist, a sweet person, and a suave person are all etymologically pursuing the same thing — sweetness.