sinner; evildoer; wrongdoer
「罪人」 has another reading with different meanings.
自らを罪人と呼んだ。
He called himself a sinner.
彼は神の前で自分が罪人であることを認めた。
He acknowledged before God that he was a sinner.
罪人とみなされないよう誠実に生きることが大切だと教えられた。
I was taught that it's important to live honestly so as not to be seen as a sinner.