vendetta

Short definition from Wiktionary

Noun

1. 1
   Revenge.
2. 2
   A bitter, destructive feud, normally between two families, clans, or factions, in which each injury or slaying is revenged: a blood feud.
3. 3
   A motivational grudge against a person or faction, which may or may not be reciprocated; the state of having it in for someone.