In today’s popular culture, swearing, or using bad language, is extremely common. At first glance, it doesn’t appear to be a sin, as it doesn’t always hurt someone.
Technically speaking, the use of profanity is not in the Catechism of the Catholic Church, but it does fall under a few different categories.
Using the Lord’s name in vain
First of all, whenever someone uses the Lord’s name in their swearing, it is a direct violation of the second commandment.
The second commandmentforbids the abuse of God’s name, i.e., every improper use of the names of God, Jesus Christ, but also of the Virgin Mary and all the saints.CCC 2146
This is probably the most obvious way that swearing can be a sin, as it does not treat God’s name with respect.
Calling other people names
The next way that swearing can be a sin is by calling other people vulgar names.
God calls each one by name. Everyone’s name is sacred. The name is the icon of the person. It demands respect as a sign of the dignity of the one who bears it.CCC 2158
Calling someone a profane name is another clear example of how a person can violate the second commandment.
Foul language in general
After the above examples, there is more gray area, as the Church doesn’t specifically list every single curse word in the Catechism.
However, the Bible does repeatedly stress the need to avoid all “foul language.”
But now you must put them all away: anger, fury, malice, slander, and obscene language out of your mouths.Colossians 3:8
It is not what enters one’s mouth that defiles that person; but what comes out of the mouth is what defiles one.Matthew 15:11
As with all sin, a person must know that it is a sin and say these words with full consent. Sometimes we may let one slip, and this isn’t always easy to stop.
The key is to try and let our language lift other people up, instead of bringing them down.