擒奸讨暴 qínjiān-tǎobào
[capture troublemakers and fight evil-forces] 奸、暴:指坏人和豪强。谓讨伐、捉拿坏人与豪强
卿在郡以来,擒奸讨暴,百姓获安。——曹操《褒扬泰山太守吕虔令》