The Collaborative International Dictionary of English v.0.48:

Reprehensible \Rep`re*hen"si*ble\ (-h?n"s?-b'l), a. [L.
   reprehensibilis: cf. F. r['e]pr['e]hensible.]
   Worthy of reprehension; culpable; censurable; blamable. --
   Rep`re*hen"si*ble*ness, n. -- Rep`re*hen"si*bly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

reprehensible
    adj 1: bringing or deserving severe rebuke or censure; "a
           criminal waste of talent"; "a deplorable act of
           violence"; "adultery is as reprehensible for a husband as
           for a wife" [syn: condemnable, criminal,
           deplorable, reprehensible, vicious]

Moby Thesaurus II by Grady Ward, 1.0:

113 Moby Thesaurus words for "reprehensible":
   abominable, accusable, amiss, arraignable, arrant, at fault,
   atrocious, awful, bad, base, beastly, beneath contempt, black,
   blamable, blameful, blameworthy, brutal, censurable, chargeable,
   contemptible, criminal, culpable, damnable, dark, deplorable,
   despicable, detestable, dire, disgraceful, disgusting, dreadful,
   egregious, enormous, evil, execrable, faulty, fetid, filthy,
   flagitious, flagrant, foul, fulsome, grievous, gross, guilty,
   hateful, heinous, horrible, horrid, impeachable, implicated,
   improper, imputable, inculpated, indictable, infamous, iniquitous,
   involved, knavish, lamentable, loathsome, lousy, low, monstrous,
   nasty, naughty, nefarious, noisome, notorious, obnoxious, odious,
   offensive, open to criticism, outrageous, peccant, pitiable,
   pitiful, rank, regrettable, reproachable, reprobate, reprovable,
   repulsive, rotten, sad, scandalous, schlock, scurvy, shabby,
   shameful, shocking, shoddy, sinful, sordid, squalid, terrible,
   to blame, too bad, unclean, unforgivable, unholy, unpardonable,
   unspeakable, unworthy, vicious, vile, villainous, wicked, woeful,
   worst, worthless, wretched, wrong