At a glance
～せいで means "because of" or "due to" when the result is bad. It often shows blame or a complaint about the cause.
[Cause (plain form)] せいで、[bad result]。
[Noun] の せいで、[bad result]。
雨のせいで、試合が中止になりました。 Because of the rain, the game was canceled.
How to form it
| Attaches to | Form | Example |
|---|---|---|
| Verb | plain form + せいで | 寝坊したせいで "because I overslept" |
| Verb (negative) | ～ない / ～なかった + せいで | 寝なかったせいで "because I didn't sleep" |
| い-adjective | ～い + せいで | 寒いせいで "because it's cold" |
| な-adjective | ～な + せいで | 下手なせいで "because I'm bad at it" |
| な-adjective (past) | ～だった + せいで | 静かだったせいで "because it was quiet" |
| Noun | ～の + せいで | 雨のせいで "because of the rain" |
| Noun (past) | ～だった + せいで | 病気だったせいで "because I was sick" |
せいで itself has no polite form. To make the sentence polite, use a polite verb in the result: 遅刻しました.
At the end of a sentence, use せいだ / せいです: 遅刻したのは電車のせいです。 "It's the train's fault that I was late."