bitter regret
Archaic literary term for deep remorse, often over a missed opportunity or irreversible mistake. Found in classical Chinese-influenced texts.
「噬臍」 is an old expression meaning irreparable regret, from the image of trying to bite one's own navel but being unable to reach it.
Archaic kanji form; the word is rarely used in modern Japanese.
Variant kanji form; also archaic.
From classical Chinese; the characters 噬 (bite) and 臍 (navel) form an idiom for regret over something that cannot be undone, akin to 'biting one's navel' in frustration.