Nouns

(n)slanderwords falsely spoken that damage the reputation of another
(n)aspersion, calumny, slander, defamation, denigrationan abusive attack on a person's character or good name

Verbs

(v)defame, slander, smirch, asperse, denigrate, calumniate, smear, sully, besmirchcharge falsely or with malicious intent; attack the good name and reputation of someone“The journalists have defamed me!”, “The article in the paper sullied my reputation”