calumnious       
adjective  formal uk/kəˈlʌm.ni.əs/ us/kəˈlʌm.ni.əs/
 毁谤的;恶意中伤的;污蔑的
false and damaging to someone's reputation
  Most of the article is just a calumnious personal attack. 这篇文章大部分只是诽谤性的人身攻击。 
 - More examples
 - The suggestion that he misappropriated funds is calumnious and politically motivated.
 - These vile aspersions against his character proved to be false and calumnious.
 - People have a right to protection from such calumnious insinuations.
 - The address contained a calumnious and insulting accusation.