character assassination
noun [ C or U ] uk/ˈkær.ɪk.tər ə.sæs.ɪˌneɪ.ʃən/ us/ˈker.ɪk.tɚ ə.sæs.ɪˌneɪ.ʃən/
（尤指报纸或电视上不公平的）人格诋毁，人身攻击，诽谤
an intentional attempt to spoil the reputation of a person by criticizing them severely, especially unfairly, in the newspapers or on television