The Collaborative International Dictionary of English v.0.48:

Sanctimonious \Sanc`ti*mo"ni*ous\, a. [See Sanctimony.]
   1. Possessing sanctimony; holy; sacred; saintly. --Shak.
      [1913 Webster]

   2. Making a show of sanctity; affecting saintliness;
      hypocritically devout or pious. "Like the sanctimonious
      pirate." --Shak.
      [1913 Webster] -- Sanc`ti*mo"ni*ous*ly, adv. --
      Sanc`ti*mo"ni*ous*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sanctimonious
    adj 1: excessively or hypocritically pious; "a sickening
           sanctimonious smile" [syn: holier-than-thou,
           pietistic, pietistical, pharisaic, pharisaical,
           sanctimonious, self-righteous]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "sanctimonious":
   Pecksniffian, Quakerish, Tartuffian, Tartuffish, Victorian,
   affected, canting, censorious, deceiving, demure, false, fanatical,
   goody, goody-goody, hidebound, holier-than-thou, hypocritic,
   hypocritical, insincere, mealy-mouthed, mealymouthed,
   mid-Victorian, narrow, oily, old-maidish, overdevout, overmodest,
   overreligious, overrighteous, overzealous, pecksniffian, pharisaic,
   pharisaical, pharisean, pietistic, pious, priggish, prim, prudish,
   puritanical, sanctified, self-righteous, simon-pure, smug,
   sniveling, snuffling, stiff-necked, straitlaced, stuffy,
   ultrareligious, unctuous, zealotic, zealous