The Collaborative International Dictionary of English v.0.48:

Unlace \Un*lace"\, v. t. [1st un- + lace.]
   [1913 Webster]
   1. To loose by undoing a lacing; as, to unlace a shoe.
      [1913 Webster]

   2. To loose the dress of; to undress; hence, to expose; to
      disgrace.
      [1913 Webster]

            What's the matter,
            That you unlace your reputation thus? --Shak.
      [1913 Webster]

   3. (Naut.) To loose, and take off, as a bonnet from a sail,
      or to cast off, as any lacing in any part of the rigging
      of a vessel. --Totten.
      [1913 Webster]

WordNet (r) 3.0 (2006):

unlace
    v 1: undo the ties of; "They untied the prisoner" [syn: untie,
         unbrace, unlace] [ant: bind, tie]