impugnation
noun
im·pugna·tion
plural -s
1
ˌimˌpəgˈnāshən
obsolete : attack, opposition 2
ˌimˌpyüˈn-
archaic : impugnment 
Word History
Etymology
Middle English impugnacioun, impungnacioun, from Middle French or Latin; Middle French impugnation, from Latin impugnation-, impugnatio, from impugnatus (past participle of impugnare to impugn) + -ion-, -io -ion