mania [LME] Mania goes back via post-classical Latin mania ‘mental disorder’ to ancient Greek mania ‘madness, inspired frenzy’, based on mainesthai ‘to rage, be furious, in a frenzy, inspired’, source also of the wild Greek maenads [LME]. It initially came into English meaning ‘madness, frenzy’ and did not gain the sense ‘obsession, excessive enthusiasm’ until the end of the 17th century.