unscrupulous

from WordNet (r) 3.0 (2006)

unscrupulous
    adj 1: without scruples or principles; "unscrupulous politicos
           who would be happy to sell...their country in order to
           gain power" [ant: {scrupulous}]

from The Collaborative International Dictionary of English v.0.48

Unscrupulous \Un*scru"pu*lous\, a.
   Not scrupulous; unprincipled. -- {Un*scru"pu*lous*ly}, adv.
   -- {Un*scru"pu*lous*ness}, n.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

78 Moby Thesaurus words for "unscrupulous":
      amoral, artful, conscienceless, corrupt, corrupted, crafty,
      criminal, crooked, cunning, dark, deceitful, devious, dishonest,
      dishonorable, disingenuous, doubtful, dubious, evasive, evil,
      faithless, false, felonious, fishy, fraudulent, ill-got,
      ill-gotten, immoral, improper, inaccurate, indirect, inexact,
      insidious, knavish, mercenary, not kosher, perfidious,
      questionable, roguish, rotten, scheming, shady, shameless, shifty,
      sinister, slippery, sly, sneaky, stick-at-nothing, suspicious,
      treacherous, tricky, unconscienced, unconscientious,
      unconscionable, uncritical, underhand, underhanded, unethical,
      unexacting, unfinical, unfussy, unmeticulous, unpainstaking,
      unparticular, unprecise, unprincipled, unpunctilious, unpunctual,
      unrigorous, unsavory, unseemly, unstraightforward, untrustworthy,
      venal, wicked, without remorse, without shame, wrongful