The Collaborative International Dictionary of English v.0.48:

Nostalgic \Nos*tal"gic\, a. [Cf. F. nostalgique.]
   Of or pertaining to nostalgia; affected with nostalgia.
   [1913 Webster]

WordNet (r) 3.0 (2006):

nostalgic
    adj 1: unhappy about being away and longing for familiar things
           or persons