The Collaborative International Dictionary of English v.0.48:

holier-than-thou \holier-than-thou\ adj.
   being excessively or hypocritically pious while condemning
   others as being less virtuous than oneself.

   Syn: pietistic, pietistical, pharisaic, pharisaical,
        sanctimonious, self-righteous.
        [WordNet 1.5 +PJC]

WordNet (r) 3.0 (2006):

holier-than-thou
    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:

23 Moby Thesaurus words for "holier-than-thou":
   Pecksniffian, Tartuffian, Tartuffish, affected, canting, false,
   goody, goody-goody, hypocritic, hypocritical, insincere,
   mealymouthed, oily, pharisaic, pharisean, pietistic, pious,
   sanctified, sanctimonious, self-righteous, simon-pure, sniveling,
   unctuous