Synonyms for Advocate (same or very similar meaning)
WordNet sense 1 (a lawyer who pleads cases in court):
counsel, counsellor, counselor, pleader, counselor-at-lawWordNet sense 2 (a person who pleads for a cause or propounds an idea):
exponent, proponent, advocatorWordNet sense 3 (push for something):
recommend, urgeWordNet sense 4 (speak, plead, or argue in favour of):
preachFrom the ODE community, based on WordNetadd/edit