The Collaborative International Dictionary of English v.0.48:

Jugoslavian \Jugoslavian\ prop. n.
   a native or inhabitant of Yugoslavia. [Also spelled
   Yugoslavian.]

   Syn: Yugoslav, Jugoslav, Yugoslavian.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Jugoslavian
    n 1: a native or inhabitant of Yugoslavia [syn: Yugoslav,
         Jugoslav, Yugoslavian, Jugoslavian]