repudiator

/rɪˈpjuːdiˌeɪtər/
noun
  1. A person who refuses to accept or support something, such as a belief, claim, or agreement.
    • The repudiator of the treaty argued that it was unfair to both sides.
    • The politician was known as a repudiator of any policy that raised taxes.
    • As a repudiator of the old traditions, she pushed for modern reforms in the community.
Antonyms