mud‧sling‧ing /ˈmʌdslɪŋɪŋ/
noun [uncountable] when 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] [TahlilGaran] Dictionary of Contemporary English ▲