1. Having taken on a position, role, or responsibility without being officially chosen, elected, or appointed by others
He is a self-appointed expert on modern art.
Ele é um autoproclamado especialista em arte moderna.
2. Claiming authority or expertise that one does not officially possess
The self-appointed leader of the group made decisions without consulting anyone.
O líder autoproclamado do grupo tomou decisões sem consultar ninguém.