to speak or write in favor of; support or urge by argument; recommend publicly

He advocated higher salaries for teachers.

a person who speaks or writes in support or defense of a person, cause, etc. (usually fol. by of )

an advocate of peace.

a person who pleads for or in behalf of another; intercessor.

a person who pleads the cause of another in a court of law.

noun

antagonist , assailant , enemy , opposition , protestor

verb

assail , attack , criticize , impugn , oppose , protest

noun

apostle , attorney , backer , campaigner , champion , counsel , defender , exponent , expounder , lawyer , pleader , promoter , proponent , proposer , speaker , spokesperson , supporter , upholder , advocate , advocatus diaboli , agent , apologist , barrister , counselor , exemplifier , hierophant , paladin , paraclete , paranymph , partisan , propagandist , protagonist , vindicator

verb

advance , advise , argue for , back , be in corner , bless , bolster , boost * , brace up , build up , campaign for , champion , countenance , defend , encourage , favor , further , get on bandwagon , give a leg up , give a lift , go for , go to bat for * , go with , hold with , justify , plead for , plug * , plump for * , press for , promote , propose , push , recommend , ride shotgun for , root for , run interference for , say so , side , speak for , spread around , stump for , support , tout , uphold , urge , vindicate , endorse , get behind , plump for , side with , stand behind , stand by , advertise , beg , commend , desiderate , espouse , plead , plug