How to say "Regret" in Japanese

When translating "regret" into Japanese, you must choose carefully between 無念 and 会稽. In Japanese, 無念 (むねん (munen)) is typically associated with "regret; chagrin; mortification; frustration (at not being able to achieve something)" (Syllabus Level: N2) and represents Expresses deep regret, often combined with frustration or disappointment, especially when one could not achieve something despite best efforts, or when something regrettable happens. It implies a strong emotional state of having been thwarted or having left something undone.. On the other hand, 会稽 (かいけい (kaikei)) maps to "regret, remorse, self-reproach" (Syllabus Level: N1) and represents 過去の失敗や過ちを深く反省し、後悔する気持ちを表す、やや硬い表現です。自己への批判的な視点を含みます。/ A somewhat formal expression for deeply reflecting on past failures or mistakes and feeling remorse. It includes a critical self-perspective.. A literal translation of "regret" can often sound unnatural to native Japanese speakers if mixed up!