turn against (third-person singular simple present turns against, present participle turning against, simple past and past participle turned against)

  1. (transitive, idiomatic) To rebel or oppose to something formerly supported.
    They turned against their leader.
  2. (transitive, intransitive) To set against or in opposition to something.
    She turned her umbrella against the wind.
    She turned against the wind.
    She turned him against his friends.
  3. (transitive, idiomatic) To use to the disadvantage or injury of.
    His argument was turned against him.
    They turned their arms against their former allies.