advocate

[1]	support , champion , back , endorse , uphold , recommend , stand behind , second , favour , speak/plead/argue for/in favour of
[2]	recommend , urge
[3]	preach

[1]	advocator , proponent , exponent
[2]	counsel , supporter , champion , counselor , counsellor , backer , upholder , counselor-at-law , pleader , second , exponent , proponent , patron , defender , apologist
[3]	lawyer , counsel , intercessor , (Brit) barrister , solicitor , (US) attorney , counselor-at-law