インターネットポリス

noun

Internet police

Refers to individuals or groups who monitor online behavior and enforce rules, often in a self-appointed or vigilante manner. Can be used seriously or sarcastically.

• 彼かれはネット上じょうで荒あらしを見みつけるとすぐに通つう報ほうする、いわゆるインターネットポリスだ。

  He's a so-called Internet police, reporting trolls as soon as he finds them online.