expression, suru verb (irregular)
blame (someone/something); lay the blame on
Used in the pattern 〜のせいにする to attribute fault or responsibility to a person, thing, or situation. Often implies an unfair or subjective assignment of blame.
彼は自分の失敗を他人のせいにした。
He blamed his own failure on others.
天気のせいにしないで、ちゃんと準備しよう。
Don't blame the weather; let's prepare properly.