expression, ichidan verb
take the law into one's own hands; administer vigilante justice
Used when someone punishes another person without legal authority, often implying a group or mob action.
村人たちは泥棒に私刑を加えた。
The villagers took the law into their own hands against the thief.
ネット上で個人情報を晒し
It is unacceptable to dox someone and administer vigilante justice online.