ETYM Italian.
A feud in which members of the opposing parties murder each other; SYN. blood feud.
Any prolonged feud, in particular one in which the relatives of a dishonored or murdered person seek revenge on the wrongdoer or members of the family. The tradition is Mediterranean, known in Europe and the US as a way of settling wrongs in Corsica, Sardinia, and Sicily, as practiced by the Mafia.