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]

Moby Thesaurus II by Grady Ward, 1.0:

116 Moby Thesaurus words for "disengage":
   abrupt, abstract, alienate, back down, back out, beat a retreat,
   break loose, break out, break with, cast off, cast out, clear,
   cut adrift, cut loose, cut off, cut out, delete, depart, detach,
   disarticulate, disburden, disconnect, disembarrass, disembroil,
   disencumber, disentangle, disinvolve, disjoin, disjoint, dislodge,
   dissociate, disunite, divide, divorce, doff, draw back, draw off,
   eject, estrange, expel, extricate, fall back, free, free up,
   get away from, get out, get out of, get rid of, give ground,
   give place, go back, isolate, leave, liberate, loose, loosen,
   move back, part, pull away, pull back, pull out, release, remove,
   retire, retreat, run back, segregate, separate, sequester,
   set apart, set aside, set free, shake off, shut off, split,
   stand aloof, stand apart, stand aside, stand back, step aside,
   subtract, take off, tear loose, throw off, throw out, unbar,
   unbind, unbolt, unbuckle, unbutton, unchain, unclasp, unclutter,
   uncouple, undo, unfasten, unfetter, unglue, unhook, unknot, unlace,
   unlatch, unleash, unlock, unloose, unloosen, unravel, unscramble,
   unsnarl, unstick, unstrap, untangle, untie, unyoke, weigh anchor,
   withdraw