The Collaborative International Dictionary of English v.0.48:

Uncharge \Un*charge"\, v. t. [1st pref. un- + charge.]
   [1913 Webster]
   1. To free from a charge or load; to unload. --Wyclif.
      [1913 Webster]

   2. To free from an accusation; to make no charge against; to
      acquit. --Shak.
      [1913 Webster]