Someone who advocates for these actions.
A person who maintains natural areas or protects threatened species.
A person who is employed to advance the interests of his or her employer, especially in a vigorous manner using such methods as political lobbying, legal advocacy, or persuasion.
A person who is employed as an armed guard, enforcer, or mercenary and who is prepared to use gunplay or similar violent methods in order to assert the interests of his or her employer.