Catechism of the Catholic Church §2553 — excerpt
Envy is sadness at the sight of another's goods and the immoderate desire to have them for oneself. It is a capital sin.
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.