Source : Webster's Revised Unabridged Dictionary (1913)

Untwine \Un*twine"\, v. t. [1st pref. un- + twine.]
   To untwist; to separate, as that which is twined or twisted;
   to disentangle; to untie.

         It requires a long and powerful counter sympathy in a
         nation to untwine the ties of custom which bind a
         people to the established and the old.   --Sir W.
                                                  Hamilton.

Untwine \Un*twine"\, v. i.
   To become untwined. --Milton.

Source : WordNet®

untwine
     v : undo what has been twined together; "untwine the strings"
         [ant: {intertwine}]