The Collaborative International Dictionary of English v.0.48:

Disengagement \Dis`en*gage"ment\, n. [Pref. dis- + engagement:
   cf. F. d['e]sengagement.]
   1. The act of disengaging or setting free, or the state of
      being disengaged.
      [1913 Webster]

            It is easy to render this disengagement of caloric
            and light evident to the senses.      --Transl. of
                                                  Lavoisier.
      [1913 Webster]

            A disengagement from earthly trammels. --Sir W.
                                                  Jones.
      [1913 Webster]

   2. Freedom from engrossing occupation; leisure.
      [1913 Webster]

            Disengagement is absolutely necessary to enjoyment.
                                                  --Bp. Butler.
      [1913 Webster]

WordNet (r) 3.0 (2006):

disengagement
    n 1: the act of releasing from an attachment or connection [syn:
         detachment, disengagement]
    2: to break off a military action with an enemy [syn:
       disengagement, fallback, pullout]