遺憾
いかん regrettable; unsatisfactory
Why it means this
遺 (left over) + 憾 (regret) — regret; 'regrettable' — a stock word of diplomatic disapproval (遺憾の意を表する; 遺憾なく, fully, without reserve).
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.