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regrettable; disappointing; unfortunate
precious; dear; valuable
too good for; deserving better
almost (but not quite); close (but no cigar)
あと一点で合格だったのに惜しい。
It is regrettable that I was one point short of passing.
あと一点で合格だったので本当に惜しかった。
It was truly disappointing since I was just one point short of passing.
まだチャンスはあるから惜しくないよ。
There are still chances left, so it's not something to regret.