プログレッシブ和英中辞典(第4版)の解説
いちじ【一事】
この一事でも彼の善良さが分かる
This one instance is enough to show his goodness.
一事が万事で彼女はなんでもいい加減にやる
She does everything carelessly.
一事不再議
the principle of not taking up an item once voted on during the same session
一事不再理
prohibition against double jeopardy