mudslinging
From Longman Dictionary of Contemporary Englishmudslingingmud‧sling‧ing /ˈmʌdslɪŋɪŋ/ noun [uncountable] CRITICIZEwhen someone says bad and often untrue things about someone in order to make other people have a low opinion of them There has been a lot of political mudslinging in the battle for votes. —mudslinger noun [countable]Examples from the Corpusmudslinging• Haze says he is angry about the mudslinging in the campaign.