The Collaborative International Dictionary of English v.0.48:

Arnaut \Ar*naut"\ Arnaout \Ar*naout"\, n. [Turk. Arnaut, fr.
   NGr. ?, for ?.]
   An inhabitant of Albania and neighboring mountainous regions,
   specif. one serving as a soldier in the Turkish army.
   [Webster 1913 Suppl.]