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