1) French word used in English 
to take by storm; to overcome
• (v. t.) To take by assault; to storm; to overcome; to vanquish; as, to expugn cities; to expugn a person by arguments.
Ex·pugn' (ĕks*pūn') transitive verb [ Latin expugnare ; ex out + pugnare to fight, pugna fight. Confer Impugn .] To take by assault; to storm; to overcome; to vanquish; as, to expugn cities; to expugn a person by arguments. 
expugn 1. To take by assault; to storm; to overcome; to vanquish; as, to expugn cities of criminals. 2. To conquer; to take by assault.