The Collaborative International Dictionary of English v.0.48:

Pharisee \Phar"i*see\ (f[a^]r"[i^]*s[=e]), n. [L. Pharisaeus,
   Gr. Farisai^os, from Heb. p[=a]rash to separate.]
   One of a sect or party among the Jews, noted for a strict and
   formal observance of rites and ceremonies and of the
   traditions of the elders, and whose pretensions to superior
   sanctity led them to separate themselves from the other Jews.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pharisee
    n 1: a self-righteous or sanctimonious person
    2: a member of an ancient Jewish sect noted for strict obedience
       to Jewish traditions

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "pharisee":
   Holy Willie, Joseph Surface, Mawworm, Pecksniff, Pharisee,
   Tartuffe, affecter, canter, canting hypocrite, dissembler,
   dissimulator, fair-weather friend, false friend, formalist,
   hypocrite, lip, lip server, lip worshiper, mealymouth, phony,
   pietist, pious fraud, poser, ranter, religionist,
   religious hypocrite, sanctimonious fraud, sniveler, snuffler,
   spiritual humbug, summer soldier, whited sepulcher