The Collaborative International Dictionary of English v.0.48:

Unfix \Un*fix"\, v. t. [1st pref. un- + fix.]
   1. To loosen from a fastening; to detach from anything that
      holds; to unsettle; as, to unfix a bayonet; to unfix the
      mind or affections.
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   2. To make fluid; to dissolve. [R.]
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            The mountain stands; nor can the rising sun
            Unfix her frosts.                     --Dryden.
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