Do we still use the terms mortal and venial in reference to sin?
Mortal (deadly) and venial are still terms used by the Church to distinguish serious sin from less serious sin (cf. CCC 1855). Mortal sin is mentioned also in 1 John 5:16–17: “If any one sees his brother committing what is not a mortal sin, he will ask, and God will give him life for those whose sin is not mortal. There is sin which is mortal; I do not say that one is to pray for that. All wrongdoing is sin, but there is sin which is not mortal.”