a. 惋惜的, 遗憾的, 抱歉的

[ adj ]
feeling or expressing regret or sorrow or a sense of loss over something done or undone
<adj.all>
felt regretful over his vanished youthregretful over mistakes she had made
he felt bad about breaking the vase

Regretful \Re*gret"ful\ (-f?l), a.
Full of regret; indulging in regrets; repining. --
{Re*gret"ful*ly}, adv.