悔しい
くやしい
kuyashii
= the frustrated, mortified feeling of losing, failing, or being wronged when you know you could have done better
English doesn’t have one word for the sting of losing a game you trained hard for, or missing an answer you actually knew. Kuyashii covers that exact feeling: part frustration, part regret, part “this shouldn’t have happened” defiance, all at once.
Kuyashii is what you feel when a gap opens up between what you’re capable of and what actually happened, and it stings precisely because you cared and believed you could have done better. It shows up after losing a close match, blowing an exam question you’d studied, or watching someone dismiss your effort unfairly. Crucially, it is not passive sadness. Where zannen (残念) is mild, resigned disappointment about an outcome you had little stake in, and kanashii (悲しい) is sadness that turns inward, kuyashii pushes outward. It has an edge of “I won’t let this happen again” built into it, which is why it’s so tightly linked to motivation. The verb kuyamu (悔やむ) means to feel this kind of regret, the noun kuyashisa (悔しさ) names the feeling itself as a thing you carry, and athletes will shout kuyashii! the instant they lose, sometimes before the tears even start.
Don’t reach for a plain “regret” translation — that’s closer to koukai (後悔), which is about a decision you made. Kuyashii is about an outcome that happened to you or that you fell short of, and it’s a much more physical, emotional word than “regret” suggests. It’s also not “sad”: a learner who translates it as sad misses the fight still in it. You’ll hear it constantly in sports commentary and post-game interviews, plus set phrases like kuyashi-namida (悔し涙, tears of frustration, wept while still angry rather than just grieving) and kuyashigaru (悔しがる, to visibly show that you feel this way — clenching fists, biting a lip, slamming a fist on the table).
Everyday use
決勝で負けて本当に悔しい。
Kesshou de makete hontou ni kuyashii.
Losing in the finals is really frustrating — I know we could’ve won.
Casual / Social Media
あと1点で満点だった…悔しすぎる！
Ato itten de manten datta… kuyashisugiru!
One point short of a perfect score… so frustrating!
Formal / Cultural context
あの時の悔しさがあったから、今の自分がある。
Ano toki no kuyashisa ga atta kara, ima no jibun ga aru.
It’s because of that frustration back then that I am who I am today.
In Japanese schools and sports clubs, kuyashisa is treated less as a feeling to be soothed away and more as raw material for growth. A coach seeing a crying athlete after a loss is unlikely to simply comfort them; more often the moment is framed as proof the player cares enough to improve, and that energy is expected to feed directly into the next round of practice.
This is closely tied to the idea of gambaru (頑張る, to push through and try one’s hardest). Kuyashii is often described as the emotional fuel that makes gambaru possible after a setback — without feeling the sting of falling short, there’s less reason to grind through the next practice session. Post-match interviews with Japanese athletes frequently include the phrase, said with a slight edge, as a public commitment to come back stronger rather than an admission of defeat.
Because of this framing, kuyashii carries a subtly positive undertone that its closest English equivalents lack. Feeling it, and especially showing it, is generally seen as a sign of seriousness and character rather than something to hide, which is part of why the word appears so often in stories about perseverance, from youth baseball to entrance-exam prep.