black mood

Origin

Long before modern psychology, the ancient Greeks believed human temperament was governed by four bodily fluids, or 'humors.' One of these, 'melaina chole'—literally 'black bile'—was thought to cause a condition they called melancholia. This wasn't just ordinary sadness; it was a profound, persistent gloom, often accompanied by irritability and a lack of energy. The connection was clear: an excess of black bile caused a 'black mood.' Though the humoral theory eventually faded into medical history, the powerful imagery of black as the color of sorrow, despair, and ill-temper stuck, giving us the enduring phrase 'black mood' as a concise way to describe a state of deep emotional darkness.