regretful

from WordNet (r) 3.0 (2006)

regretful
    adj 1: feeling or expressing regret or sorrow or a sense of loss
           over something done or undone; "felt regretful over his
           vanished youth"; "regretful over mistakes she had made";
           "he felt bad about breaking the vase" [syn: {regretful},
           {sorry}, {bad}] [ant: {unregretful}, {unregretting}]

from The Collaborative International Dictionary of English v.0.48

Regretful \Re*gret"ful\ (-f?l), a.
   Full of regret; indulging in regrets; repining. --
   {Re*gret"ful*ly}, adv.
   [1913 Webster] re-group

from Moby Thesaurus II by Grady Ward, 1.0

54 Moby Thesaurus words for "regretful":
      apologetic, ashamed, baffled, balked, betrayed, bilked, blasted,
      blighted, chapfallen, conscience-smitten, conscience-stricken,
      contrite, crestfallen, crossed, crushed, dashed, defeated,
      disappointed, dished, disillusioned, dissatisfied, foiled,
      frustrated, full of remorse, guilty, ill done-by, ill-served,
      let down, mournful, out of countenance, penitent, remorseful,
      repentant, repining, rueful, sad, self-accusing, self-condemning,
      self-convicting, self-debasing, self-flagellating,
      self-humiliating, self-punishing, self-reproaching, shamefaced,
      shamefast, shameful, sorely disappointed, sorrowful, sorry, soured,
      thwarted, unhappy about, wistful