Cacoethes \kak-oh-EE-theez\ , noun;
1. An irresistible urge; mania
This word, with the meaning "itch for doing something", dates to the 1560's and comes from Greek kakoethes via Latin. Kakoethes ("ill-habit, wickedness, itch for doing (something)") comes from kakos ("bad") + ethe- ("disposition, character"). The most famous use of this word is in Juvenal's insanabile scribendi cacoethes, or "incurable passion for writing".
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Saturday, January 29
Etymologies come from the Oxford English Dictionary and/or Etymonline.com