Synonyms for Slander (same or very similar meaning)
WordNet sense 1 (an abusive attack on a person's character or good name):
aspersion, calumny, defamation, denigrationWordNet sense 2 (charge falsely or with malicious intent; attack the good name and reputation of someone):
besmirch, calumniate, defame, denigrate, smear, smirch, sully, asperseFrom the ODE community, based on WordNetadd/edit