noun
self-righteous person; self-appointed rule enforcer
Internet slang, derogatory. Refers to someone who aggressively pushes their own sense of justice or rules on others, often in online communities.
掲示板にすぐ正義マンが現れて、細かいルール違反を指摘し始める。
A self-righteous person quickly appears on the forum and starts pointing out minor rule violations.
あの正義マンは自分の意見を押し付けてくるから面倒だ。
That self-proclaimed enforcer is annoying because they push their own opinions on you.