1. regrettable; disappointing; unfortunate
そりゃ惜しいことをしたな。Well, that's a real shame.
2. precious; dear; valuable
この少年のためならば命も惜しくない。For this boy's sake, I wouldn't even begrudge my life.
3. too good for; deserving better
彼は軍人をやらせておくには惜しい男だな。He's too good a man to leave as a mere soldier.
4. almost (but not quite); close (but no cigar)
さっきのが一番惜しかった。That last one was the closest.