The Collaborative International Dictionary of English v.0.48:

Miscreant \Mis"cre*ant\, n. [OF. mescreant, F. m['e]cr['e]ant;
   pref. mes- (L. minus less) + p. pr. fr. L. credere to
   believe. See Creed.]
   [1913 Webster]
   1. One who holds a false religious faith; a misbeliever.
      [Obs.] --Spenser. De Quincey.
      [1913 Webster]

            Thou oughtest not to be slothful to the destruction
            of the miscreants, but to constrain them to obey our
            Lord God.                             --Rivers.
      [1913 Webster]

   2. One not restrained by Christian principles; an
      unscrupulous villain; a depraved person; a vile wretch.
      --Addison.

The Collaborative International Dictionary of English v.0.48:

Miscreant \Mis"cre*ant\, a.
   1. Holding a false religious faith.
      [1913 Webster]

   2. Destitute of conscience; unscrupulous; villainous; base;
      depraved. --Pope.
      [1913 Webster +PJC]

The Devil's Dictionary (1881-1906):

MISCREANT, n.  A person of the highest degree of unworth.
Etymologically, the word means unbeliever, and its present
signification may be regarded as theology's noblest contribution to
the development of our language.


Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "miscreant":
   backslider, bad egg, bad lot, base, bastard, black sheep,
   blackguard, caitiff, corrupt, criminal, crook, degenerate,
   depraved, evil, fallen angel, felon, felonious, flagitious,
   good-for-nothing, heel, hood, hoodlum, hooligan, infamous,
   iniquitous, knave, lecher, lost sheep, lost soul, lowlife,
   malefactor, malefic, malevolent, mischief-maker, mischievous, mug,
   nefarious, perverse, pervert, pimp, profligate, rapscallion,
   rascal, rascally, recidivist, recreant, reprobate, rogue, rough,
   roughneck, rowdy, ruffian, scalawag, scamp, scapegrace, scoundrel,
   scoundrelly, sorry lot, thug, trollop, unhealthy, unprincipled,
   vicious, villain, villainous, whore, wicked, wretch, wretched,
   wrongdoer