The Collaborative International Dictionary of English v.0.48:

Rushbuckler \Rush"buc`kler\, n.
   A bullying and violent person; a braggart; a swashbuckler.
   [Obs.]
   [1913 Webster]

         That flock of stout, bragging rushbucklers. --Robynson
                                                  (More's
                                                  Utopia).
   [1913 Webster]