Feud

A feud (pronounced /ˈfjuːd/) (also called blood feud or vendetta) is a long-running argument or fight between parties. In most cases it involves whole familles or clans. People are seen as guilty, not because they did something, but because they were seen with other people (who are considered guilty). This is called guilt by association.

Feuds start because one party thinks they were attacked, insulted, or harmed by the other party. Intense feelings of resentment trigger the initial revenge, which causes the other party to feel the same way. The dispute is then fueled by a long-running cycle of retaliatory violence. This ongoing cycle of provocation and retaliation makes it very difficult to end the feud peacefully. Feuds frequently involve the original parties' family members and/or associates. They can last for generations.

Up to the early modern period, feuds were considered legitimate legal instruments. The state or ruler even made laws for certain aspects of feuds. Once modern centralizing states asserted and enforced a monopoly on legitimate use of force, feuds became illegal.