The term "advocate" is more commonly used to refer to someone who strongly supports something ("defensor de uma causa").
There are multiple definitions - click on the translation that matches your context.
(SCOTS LAW) a lawyer who represents a client in court (Cf. barrister)
I won't be meeting my advocate again until just before the trial.
someone who puts forward a case for another person; a general term for a lawyer
Hayrat is representing the company but his father has come along with him as his advocate.
someone who strongly and publicly supports or speaks in favour of someone or something, especially in favour of a particular public plan or action
He was an advocate of equal rights for women.