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]

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "deportment":
   action, actions, activity, acts, address, affectation, air,
   bearing, behavior, behavior pattern, behavioral norm,
   behavioral science, carriage, comportment, conduct,
   culture pattern, custom, demeanor, doing, doings, folkway,
   gestures, goings-on, guise, maintien, manner, manners, method,
   methodology, methods, mien, modus vivendi, motions, movements,
   moves, observable behavior, pattern, poise, port, pose, posture,
   practice, praxis, presence, procedure, proceeding, set,
   social science, style, tactics, tone, way, way of life, ways