[syn: unblock, unfreeze, free, release]
The Collaborative International Dictionary of English v.0.48:
Unfreeze \Un*freeze"\, v. t. [1st pref. un- + freeze.]
   To thaw. [Obs.]
   [1913 Webster]
WordNet (r) 3.0 (2006):
unfreeze
    v 1: become or cause to become soft or liquid; "The sun melted
         the ice"; "the ice thawed"; "the ice cream melted"; "The
         heat melted the wax"; "The giant iceberg dissolved over the
         years during the global warming phase"; "dethaw the meat"
         [syn: dissolve, thaw, unfreeze, unthaw, dethaw,
         melt]
    2: make (assets) available; "release the holdings in the
       dictator's bank account" [syn: unblock, unfreeze, free,
       release] [ant: block, freeze, immobilise,
       immobilize]