To convert or attempt to convert someone from one religion, belief, or opinion to another. The missionaries traveled to remote villages to proselytize the local population.
To advocate or promote a belief or course of action. She often proselytizes about the benefits of a vegan lifestyle to her friends.
To engage in proselytism; to seek to convert others to one’s faith, ideology, or cause (intransitive). Employees were instructed not to proselytize while on duty.