CCC 1862
Life in Christ›SECTION ONE MAN'S VOCATION LIFE IN THE SPIRIT›CHAPTER ONE THE DIGNITY OF THE HUMAN PERSON›IV. The Gravity of Sin: Mortal and Venial Sin
One commits venial sin when, in a less serious matter, he does not observe the standard prescribed by the moral law, or when he disobeys the moral law in a grave matter, but without full knowledge or without complete consent.