one who defends or maintains a cause or proposal; one who supports or promotes the interests of a cause or group; one who pleads the cause of another; specifically : one who pleads the cause of another before a tribunal or judicial court… See the full definition| www.merriam-webster.com
the act or process of supporting a cause or proposal : the act or process of advocating something… See the full definition| www.merriam-webster.com