The Collaborative International Dictionary of English v.0.48:

Snobbish \Snob"bish\, a.
   Of or pertaining to a snob; characteristic of, or befitting,
   a snob; vulgarly pretentious. -- Snob"bish*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

snobbish
    adj 1: befitting or characteristic of those who incline to
           social exclusiveness and who rebuff the advances of
           people considered inferior [syn: clannish, cliquish,
           clubby, snobbish, snobby]