The Collaborative International Dictionary of English v.0.48:

Deportment \De*port"ment\, n. [F. d['e]portement misconduct,
   OF., demeanor. See Deport.]
   Manner of deporting or demeaning one's self; manner of
   acting; conduct; carriage; especially, manner of acting with
   respect to the courtesies and duties of life; behavior;
   demeanor; bearing.
   [1913 Webster]

         The gravity of his deportment carried him safe through
         many difficulties.                       --Swift.
   [1913 Webster]

WordNet (r) 3.0 (2006):

deportment
    n 1: (behavioral attributes) the way a person behaves toward
         other people [syn: demeanor, demeanour, behavior,
         behaviour, conduct, deportment]