What is the Catholic teaching on cursing? It seems today that it is almost the vernacular for college students. Is it ever appropriate to cuss?I scoured the Catechism and was unable to find anything specifically about "cussing" or using foul language. But, there are a few articles that are related, and these might be helpful.
As Christians, we must comform our words to the mind of Christ and follow His example (no. 1694). God's presence and His truth must be honored in all speech (no. 2153). He is "the Lord of all speech" (no. 2152), and human speech is either in accord with or in opposition to God who is Truth itself (no. 2151). Living in accordance with Truth includes displaying an uprightness and sincerity in speech (no. 2468). The purpose of speech is to communicate truth (no. 2485).
Conversely, abusive language is forbidden by the fifth commandment (no. 2073), and anyone who is angry with his brother is liable to judgment (no. 2302-2303). Respect for the reputation of persons forbids every attitude and word likely to cause them unjust injury (no. 2477).
Finally, cussing often includes taking God's name in vain, and this is certainly forbidden, as is language against the Church, the saints, and sacred things (no. 2148).
The Bible is more explicit in its condemnation of foul language. For example, see the following passages:
Mt 5:33-37 "Again you have heard that it was said to the men of old, 'You shall not swear falsely, but shall perform to the Lord what you have sworn.' 34 But I say to you, Do not swear at all, either by heaven, for it is the throne of God, 35 or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King. 36 And do not swear by your head, for you cannot make one hair white or black. 37 Let what you say be simply 'Yes' or 'No'; anything more than this comes from evil.
Mt 15:10-11,17-20 And he called the people to him and said to them, "Hear and understand: 11 not what goes into the mouth defiles a man, but what comes out of the mouth, this defiles a man." 17 Do you not see that whatever goes into the mouth passes into the stomach, and so passes on? 18 But what comes out of the mouth proceeds from the heart, and this defiles a man. 19 For out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander. 20 These are what defile a man; but to eat with unwashed hands does not defile a man."
Eph 4:29 Let no evil talk come out of your mouths, but only such as is good for edifying, as fits the occasion, that it may impart grace to those who hear.
1 Pet 3:10 For "He that would love life and see good days, let him keep his tongue from evil and his lips from speaking guile;
Jas 1:26 If any one thinks he is religious, and does not bridle his tongue but deceives his heart, this man's religion is vain.
Jas 3:3-10 If we put bits into the mouths of horses that they may obey us, we guide their whole bodies. 4 Look at the ships also; though they are so great and are driven by strong winds, they are guided by a very small rudder wherever the will of the pilot directs. 5 So the tongue is a little member and boasts of great things. How great a forest is set ablaze by a small fire! 6 And the tongue is a fire. The tongue is an unrighteous world among our members, staining the whole body, setting on fire the cycle of nature, and set on fire by hell. 7 For every kind of beast and bird, of reptile and sea creature, can be tamed and has been tamed by humankind, 8 but no human being can tame the tongue--a restless evil, full of deadly poison. 9 With it we bless the Lord and Father, and with it we curse men, who are made in the likeness of God. 10 From the same mouth come blessing and cursing. My brethren, this ought not to be so.
I would like to add that using foul language is also wrong because of the scandal it causes. What kind of witness do we give to non-Christians when we speak crudely to or about each other? We are called to sanctify the world, not fall into its various vices. Also, cussing is usually symptomatic of anger, impatience, hatred, and other sentiments that are generally unbecoming of a person who is supposed to be living a life of grace, and peace, and self-mastery. It's difficult not to cuss, particularly once it becomes a habit (trust me, I know!), but this tongue of ours is a powerful weapon and we must strive to tame it.
I hope that helps.