vigilante
US
UK vigilante n: (self-appointed law enforcer)
SC 自发组织的治安维持会成员 zì fā zǔ zhī de zhì ān wéi chí huì chéng yuán
The city authorities do not want vigilantes on the streets.
vigilante adj: (relating to unofficial justice)
SC 治安维持会的 zhì ān wéi chí huì de
Vigilante groups have been battling drug gangs.