The Collaborative International Dictionary of English v.0.48:

Wallachian \Wal*la"chi*an\, a. [Also Walachian, Wallach,
   Wallack, Vlach, etc.]
   Of or pertaining to Wallachia, a former principality, now
   part of the kingdom, of Roumania. -- n. An inhabitant of
   Wallachia; also, the language of the Wallachians; Roumanian.
   [Webster 1913 Suppl.]