Catechism of the Catholic Church §2482 — excerpt
"A lie consists in speaking a falsehood with the intention of deceiving." The Lord denounces lying as the work of the devil: "You are of your father the devil, .
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Augustine, De mendacio 4, 5: PL 40: 491