Source : Webster's Revised Unabridged Dictionary (1913)

Unnature \Un*na"ture\, v. t. [1st pref. un- + nature.]
   To change the nature of; to invest with a different or
   contrary nature. [Obs.]

         A right heavenly nature, indeed, as if were unnaturing
         them, doth so bridle them [the elements]. --Sir P.
                                                  Sidney.

Unnature \Un*na"ture\, n. [Pref. un- not + nature.]
   The contrary of nature; that which is unnatural. [R.]

         So as to be rather unnature, after all, than nature.
                                                  --H. Bushnell.