プログレッシブ和英中辞典(第4版)の解説
くい【悔い】
〔悔悟〕repentance；〔残念〕regret ⇒こうかい（後悔）
悔いが残らないようにがんばれ
Do your best so that you won't regret it afterwards.
彼の判断の誤りは悔いを千載に残すことになろう
He will regret his misjudgment very deeply for many years to come.
悔いのない人生を送った
He had few regrets about his life.／There was nothing he would have changed about his life.