悔しい・口惜しい|くやしいkuyashii[3]nakadaka (mid-high)

1. i-adjectivefrustrated (over a failure, humiliation or injustice); annoyed; chagrined; (bitterly) disappointed; bitter; vexed; frustrating; annoying; regrettable
   監督かんとくはチームをトーナメント優勝ゆうしょうに今一いまいち歩あゆみという所ところまでもっていったのに悔くやしいことだった。↗

   It was annoying, as the manager took his team to a near-miss in the tournament.

• Synonym残念ざんねんNeutralNeutral in register. Covers simple regret or disappointment (「残念ながら」), not necessarily the vexed, unresigned feeling that 「悔しい」 carries after a failure or setback.
• Synonym無念むねんWrittenWritten/formal prose. Bitter, grievous regret, as in 「無念の涙」; a heavy, deep-seated feeling.
• Synonym口惜しいくちおしいWrittenRead 「くちおしい」 and rather old-fashioned; means chagrined or vexing — a different word from this headword, which is the same written form read 「くやしい」.
• Related遺憾いかんWrittenWritten/formal prose. Expresses regret, mostly in official statements (「遺憾に思う」).
• RelatedこころのこりNeutralNeutral. Lingering regret you cannot let go of (「心残りがある」); the emphasis is on unfinished feelings, not the sting of defeat.
• Antonym満足まんぞくNeutralNeutral. Satisfaction or contentment — the direct opposite of the unresigned frustration of 「悔しい」.

Use 「悔しい」 for the bitter, unresigned feeling after losing, failing or being wronged (「負けて悔しい」). For plain regret use 「残念」, for official regret 「遺憾」, for deep chagrin 「無念」, for lingering regret 「心残り」; the opposite is 「満足」.

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

1. 失敗しっぱい・屈辱くつじょくなどを経験けいけんし、諦あきらめることができず残念ざんねんに思おもうさま。