calomnier

To slander someone — spreading damaging, knowingly false claims about them, a more formal/literary register than the everyday médire (to speak ill of). Strongly associated with reputation and legal/moral wrongdoing rather than casual gossip.

• Il l'a calomniée publiquement sans aucune preuve. — He publicly slandered her without any evidence.
• La presse a été accusée de calomnier l'ancien ministre. — The press was accused of slandering the former minister.
• Elle a porté plainte pour avoir été calomniée. — She filed a complaint for being slandered.

Calomnier is a serious, almost legal accusation of deliberate falsehood — don't use it loosely for ordinary gossip or complaining about someone, which is médire or critiquer instead.

• quote "Calomniez, calomniez, il en restera toujours quelque chose" — The popularly quoted, condensed version of Basile's tirade on slander in Beaumarchais's Le Barbier de Séville (1775) — the play's actual wording differs, but this line is the one widely attributed to Beaumarchais in French culture, and the tirade itself was later made famous on stage in Rossini's operatic adaptation.