悔い|くいkui[1]atamadaka (head-high)

1. nounregret; repentance
   我わが生涯しょうがいに一いち片へんの悔くいなし。↗

   I regret nothing of my life.

• Synonym後悔こうかいNeutralThe everyday word for regret; it works as a verb too, as in 「後悔する」, and is common in conversation, while the noun 「悔い」 appears mostly in 「悔いが残る」「悔いはない」.
• Related自責の念じせきのねんWrittenWritten/formal phrase for the anguish of feeling one's own actions or mistakes were one's fault; it stresses self-blame, while 「悔い」 stresses regret felt afterward.
• Related後悔の念WrittenA written way to say regret, often in 「後悔の念に駆られる」; in meaning it is very close to 「悔い」.
• Antonym満足まんぞくNeutralFeeling fully satisfied with how things turned out, with no regrets; in one's reaction to a result it stands opposite to 「悔い」.

For 'no regrets' say 「悔いはない」 or 「悔いが残らない」. In everyday speech, regret is 「後悔する」; for guilt and self-blame, use 「自責の念」. 「後悔の念」 belongs to written prose, and 「満足」 is the opposite feeling.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 失敗しっぱいや悪わるい行おこないについて、あとになって残念ざんねんに思おもう気持きもち。