Source : Webster's Revised Unabridged Dictionary (1913)

Untune \Un*tune"\, v. t. [1st pref. un- + tune.]
   To make incapable of harmony, or of harmonious action; to put
   out of tune. --Shak.

Source : WordNet®

untune
     v 1: cause to lose one's composure [syn: {upset}, {discompose}, {disconcert},
           {discomfit}]
     2: cause to be out of tune; "Don't untune that string!" [ant: {tune}]