knock down and drag out

/ˈnɑkˌdaʊn ən ˈdræɡ ˌaʊt/
adjective
  1. Very violent, intense, or bitter, especially describing a fight or argument.
    • It was a knock-down-and-drag-out brawl between the rival gangs.
    • The two politicians had a knock-down-and-drag-out debate that lasted three hours.
    • Their divorce turned into a knock-down-and-drag-out legal battle over money.