What does せい mean?
せい is a Japanese noun meaning “fault (for something bad)” or “blame” in English. It is written as せい in hiragana, and sei in romaji. This word is part of JLPT N3 vocabulary.
Example sentences
遅れたのは雨のせいだ。
It's the rain's fault that we're late.
失敗を人のせいにするな。
Don't blame other people for your mistakes.