Source : Webster's Revised Unabridged Dictionary (1913)

Oppugn \Op*pugn"\, v. t. [imp. & p. p. {Oppugned}; p pr. & vb.
   n. {Oppugning}.] [OF. oppugner, L. oppugnare; ob (see {Ob-})
   + pugnare to fight. See {Impugn}.]
   To fight against; to attack; to be in conflict with; to
   oppose; to resist.

         They said the manner of their impeachment they could
         not but conceive did oppugn the rights of Parliament.
                                                  --Clarendon.