The Collaborative International Dictionary of English v.0.48:

Hadji \Hadj"i\ (-[i^]), n. [Ar. h[=a]jj[imac]. See Hadj.]
   [Also spelled hajji and haji.]
   1. A Mohammedan who has made a pilgrimage to Mecca; -- used
      among Orientals as a respectful salutation or a title of
      honor. --G. W. Curtis.
      [1913 Webster]

   2. A Greek or Armenian who has visited the holy sepulcher at
      Jerusalem. --Heyse.
      [1913 Webster]

WordNet (r) 3.0 (2006):

hadji
    n 1: an Arabic term of respect for someone who has made the
         pilgrimage to Mecca [syn: hajji, hadji, haji]