calumniative
/kælʊmɪˈneɪtɪv/Definitions
1. adjective
Given to calumny; having a tendency to speak falsely or maliciously of others.
“The politician’s calumniative remarks sparked outrage among the public.”
2. noun
The quality of being given to calumny.
“The politician’s calumniative nature was evident in his previous speeches.”