"itch for doing something," 1560s, from Latinized form of Greek kakoethes "ill-habit, wickedness, itch for doing (something)," from kakos "bad" (see caco-) + ethe- "disposition, character" (see ethos). Most famously, in Juvenal's insanabile scribendi cacoethes "incurable passion for writing."[cacoethes etymology, cacoethes origin, 英语词源]