The word calumny, meaning "slanderous statement", was first used in English around the 1560s and partially popularized when Shakespeare used it in Hamlet. It was borrowed from the Old French word calomnie (with the same meaning), and that was taken in the 1400s from Latin calumnia, "trickery" (also the etymon of the word challenge, on the notion of "false accusation" developing into "accusation" and eventually "confrontation"). The origin of that is calvi, meaning "to deceive", and calvi, based on cognates in Greek and Germanic languages, has been tentatively reconstructed to a Proto-Indo-European root sounding like kehl and having something to do with betrayal or lying. According to Google NGrams, literary usage of the word calumny peaked in 1796 and has been declining since.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.