Melancholia

Melancholia (from Greek μελαγχολία – melancholia, “sadness”, literally black bile), also lugubriousness, from the Latin lugere, to mourn; moroseness, from the Latin morosus, self-willed, fastidious habit; wistfulness, from old English wist: intent, or saturnine, in contemporary usage, is a mood disorder of non-specific depression, characterized by low levels of both enthusiasm and eagerness for activity.