Word Origin & History
facetious1590s, from Fr. facétieux, from facétie "a joke," from L. facetia, from facetus "witty, elegant," of unknown origin, perhaps related to facis "torch." It implies a desire to be amusing, often intrusive or ill-timed. "Facetiæ in booksellers' catalogues, is, like curious, a euphemism
for erotica." [Fowler] Related: Facetiously; facetiousness