The Collaborative International Dictionary of English v.0.48:

Shameful \Shame"ful\, a.
   1. Bringing shame or disgrace; injurious to reputation;
      disgraceful.
      [1913 Webster]

            His naval preparations were not more surprising than
            his quick and shameful retreat.       --Arbuthnot.
      [1913 Webster]

   2. Exciting the feeling of shame in others; indecent; as, a
      shameful picture; a shameful sight. --Spenser.
      [1913 Webster]

   Syn: Disgraceful; reproachful; indecent; unbecoming;
        degrading; scandalous; ignominious; infamous.
        [1913 Webster] -- Shame"ful*ly, adv. --
        Shame"ful*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

shameful
    adj 1: (used of conduct or character) deserving or bringing
           disgrace or shame; "Man...has written one of his blackest
           records as a destroyer on the oceanic islands"- Rachel
           Carson; "an ignominious retreat"; "inglorious defeat";
           "an opprobrious monument to human greed"; "a shameful
           display of cowardice" [syn: black, disgraceful,
           ignominious, inglorious, opprobrious, shameful]
    2: giving offense to moral sensibilities and injurious to
       reputation; "scandalous behavior"; "the wicked rascally
       shameful conduct of the bankrupt"- Thackeray; "the most
       shocking book of its time" [syn: disgraceful, scandalous,
       shameful, shocking]

Moby Thesaurus II by Grady Ward, 1.0:

166 Moby Thesaurus words for "shameful":
   aberrant, abnormal, abominable, arrant, ashamed, atrocious, awful,
   bad, base, beastly, beneath contempt, beneath one, black, blamable,
   blameworthy, brutal, chastening, cheap, conscience-smitten,
   conscience-stricken, contemptible, corrupt, criminal, damnable,
   dark, debasing, degrading, delinquent, demeaning, deplorable,
   despicable, detestable, deviant, dire, discreditable, disgraceful,
   disgusting, dishonorable, disreputable, dreadful, egregious,
   embarrassing, enormous, evil, execrable, fetid, filthy, flagitious,
   flagrant, foul, full of remorse, fulsome, grievous, gross, gutter,
   hardly the thing, hateful, heinous, horrible, horrid, humbling,
   humiliating, humiliative, ignominious, illegal, improper,
   inappropriate, incorrect, indecent, indecorous, infamous,
   infra dig, infra indignitatem, inglorious, iniquitous, knavish,
   lamentable, loathsome, lousy, low, mean, monstrous, mortifying,
   nasty, naughty, nefarious, noisome, not done, not the thing,
   notorious, obnoxious, odious, off-base, off-color, offensive,
   opprobrious, out-of-line, outrageous, peccant, pitiable, pitiful,
   rank, regretful, regrettable, remorseful, repining, reprehensible,
   reprobate, repulsive, rotten, rueful, sacrilegious, sad,
   scandalous, schlock, scurvy, self-accusing, self-condemning,
   self-convicting, self-debasing, self-flagellating,
   self-humiliating, self-punishing, self-reproaching, shabby, shady,
   shamefaced, shamefast, shameless, shaming, shocking, shoddy,
   sinful, sordid, sorry, squalid, terrible, too bad, unbecoming,
   unclean, undue, unfit, unfitting, unforgivable, unhappy about,
   unlawful, unpardonable, unprincipled, unrespectable, unrighteous,
   unseemly, unspeakable, unsuitable, unworthy, unworthy of one,
   vicious, vile, villainous, wicked, wistful, woeful, worst,
   worthless, wretched, wrong, wrongful