(n.) a teller of scandalous, damaging tales
Someone who gossips or tells tales that have the potential to ruin others’ reputations, or otherwise cause hurt or damage, is a tutiviller.
That’s a word dating from the sixteenth century in English at least, though its origins (as some of you clever medievalist types on Twitter we all too quick to spot) is considerably older than that.
In medieval Christian folklore, Tutivillus was the name of sprite or demon said to have the power of collecting up all the mumbled and mispronounced words muttered halfheartedly by bored attendees of Latin church services. These lexical missteps would be kept or catalogued by Tutivillus, who, on the day of your reckoning, would return from Hell to confront you with them as part of your final judgement.
Other versions of this story imbue Tutivillus with the power to collect evidence of your sins, not just your mumbled words, and say that he will confront you with all your misdeeds, lexical or otherwise, on the day of Rapture, not merely your entry to Heaven.
The folkloric origins of Tutivillus are unclear, though the Oxford English Dictionary suggests he is “a creation of monastic wit”—a kind of boogeyman for monkish novitiates. The etymological origins of his name are just as murky, though it’s likely its origins lie in a Latin word, tittivilis, for something of little value or significance—a nod to the fact that even your most minor indiscretions will matter on Judgement Day.
No matter where Tutivillus himself comes from, his name is indeed the origin of the later word tutilliver—essentially a byword for someone who knows your sins and moral missteps, and gossipingly uses them against you and your reputation.