Catechism of the Catholic Church §1991 — excerpt
Justification is at the same time the acceptance of God's righteousness through faith in Jesus Christ. Righteousness (or "justice") here means the rectitude of divine love.
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.