The Collaborative International Dictionary of English v.0.48:

Palestinian \Pal`es*tin"i*an\, Palestinean \Pal`es*tin"e*an\, a.
   Of or pertaining to Palestine.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Palestinian
    adj 1: of or relating to the area of Palestine and its
           inhabitants; "Palestinian guerrillas"
    n 1: a descendant of the Arabs who inhabited Palestine [syn:
         Palestinian, Palestinian Arab]