"knowingly utter false charges," 1550s, from Latin calumniatus, past participle of calumniari "to accuse falsely," from calumnia "slander, false accusation" (see calumny). A doublet of challenge. Related: Calumniated; calumniating.

"act of caluminating," 1540s, noun of action from calumniate (v.).

"one who falsely and knowingly accuses another of anything disgraceful or maliciously propagates false reports," 1560s, from Latin calumniator, agent noun from calumniari "to accuse falsely" (see calumniate (v.)). Related: Calumniatory.