self constituted

/ˌsɛlf ˈkɑnstɪˌtutɪd/
adjective
  1. Having appointed oneself to a position or role without outside authority.
    • The self-constituted committee had no official power but still made decisions.
    • She acted as a self-constituted expert on the topic, even though she had no training.
    • He was a self-constituted leader of the neighborhood watch group.