The Collaborative International Dictionary of English v.0.48:

Disconcertion \Dis`con*cer"tion\, n.
   The act of disconcerting, or state of being disconcerted;
   discomposure; perturbation. [R.] --State Trials (1794).
   [1913 Webster]

WordNet (r) 3.0 (2006):

disconcertion
    n 1: anxious embarrassment [syn: discomfiture, discomposure,
         disconcertion, disconcertment]