Source : Webster's Revised Unabridged Dictionary (1913)

Unbreech \Un*breech"\, v. t. [imp. & p. p. {Unbreeched}; p. pr.
   & vb. n. {Unbreching}.] [1st pref. un- + breech.]
   1. To remove the breeches of; to divest or strip of breeches.
      --Shak.

   2. (Gun.) To free the breech of, as a cannon, from its
      fastenings or coverings. --Pennant.