Catechism of the Catholic Church §1490 — excerpt
The movement of return to God, called conversion and repentance, entails sorrow for and abhorrence of sins committed, and the firm purpose of sinning no more in the future.
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.