The Collaborative International Dictionary of English v.0.48:

Disengage \Dis`en*gage"\, v. t. [imp. & p. p. Disengaged; p.
   pr. & vb. n. Disengaging.] [Pref. dis- + engage: cf. F.
   d['e]sengager.]
   To release from that with which anything is engaged,
   engrossed, involved, or entangled; to extricate; to detach;
   to set free; to liberate; to clear; as, to disengage one from
   a party, from broils and controversies, from an oath,
   promise, or occupation; to disengage the affections a
   favorite pursuit, the mind from study.
   [1913 Webster]

         To disengage him and the kingdom, great sums were to be
         borrowed.                                --Milton.
   [1913 Webster]

         Caloric and light must be disengaged during the
         process.                                 --Transl. of
                                                  Lavoisier.

   Syn: To liberate; free; loose; extricate; clear; disentangle;
        detach; withdraw; wean.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Disengage \Dis`en*gage"\, v. i.
   To release one's self; to become detached; to free one's
   self.
   [1913 Webster]

         From a friends's grave how soon we disengage! --Young.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disengage
    v 1: release from something that holds fast, connects, or
         entangles; "I want to disengage myself from his influence";
         "disengage the gears" [syn: disengage, withdraw] [ant:
         engage, lock, mesh, operate]
    2: free or remove obstruction from; "free a path across the
       cluttered floor" [syn: free, disengage] [ant: block,
       close up, impede, jam, obstruct, obturate,
       occlude]
    3: become free; "in neutral, the gears disengage" [ant:
       engage]