Source : Webster's Revised Unabridged Dictionary (1913)

Expugn \Ex*pugn"\ ([e^]ks*p[=u]n"), v. t. [L. expugnare; ex out
   + pugnare to fight, pugna fight. Cf. {Impugn}.]
   To take by assault; to storm; to overcome; to vanquish; as,
   to expugn cities; to expugn a person by arguments.