EUPHORIA

Euphoria is medically recognized as an affect (emotional and mental state) defined as a series of great elation and well-being. The term is is often used colloquially to define an emotion of intense transcendental happiness combined with an overwhelming sense of well-being. In Greek the word ἘΥΦΟΡΊΑ [frequentative from εὖ + φερεῖν] means "power of easily bearing or carrying, contentment, sense of well-being, grace of movement, fertility".
Euphoria is generally considered to be an exaggerated state resulting from psychological or pharmacological stressors and not typically achieved during the course of human experience, although some natural behaviors, such as acivities resulting in orgasm or the triumph of an athlete, can induce brief states of euphoria. Euphoria has also been cited during certain religious or spiritual rituals and meditation.
Kakaphoria, if such a were word used by the Ancient Greeks, would mean the opposite to euphoria.