assassinator

verb (used with object), as·sas·si·nat·ed, as·sas·si·nat·ing.

1. to kill suddenly or secretively, especially a politically prominent person; murder premeditatedly and treacherously.
2. to destroy or harm treacherously and viciously: to assassinate a person’s character.

verb (tr)

1. to murder (a person, esp a public or political figure), usually by a surprise attack
2. to ruin or harm (a person’s reputation, etc) by slander