I've wondered for a while now if profanity/cursing is a sin. We hear it all the time in real life and on tv, but is it actually a sin ? I've read some verses that somewhat imply it in a certain context. But I haven't seen any straightforward answer anywhere. And if cursing is a sin, then is it a major one (killing unjustly, sexual sin, etc.) or a minor one (worrying, etc), because if its a major sin then we would all be screwed.
Hello RaceBoy, as you have already seen from the Scripture verses that @Magenta's posited for us, profanity should be considered a sin (in almost every case). Here's another passage to consider too (with several commands that come with a very serious consequence, if disobedience to them is what characterizes a person's life, that is).
Ephesians 5
1 Be imitators of God, as beloved children;
2 and walk in love, just as Christ also loved you and gave Himself up for us, an offering and a sacrifice to God as a fragrant aroma.
3 But immorality or any impurity or greed must not even be named among you, as is proper among saints;
4 and ~there must be no filthiness and silly talk, or coarse jesting, which are not fitting, but rather giving of thanks.~
5 For this you know with certainty, that no immoral or impure person or covetous man, who is an idolater, has an inheritance in the kingdom of Christ and God.
There are a few cases when I do not believe that the use of profanity is sinful, just like there are certain cases when I do not believe that lying is sinful, but these ALWAYS involve necessary reactions to certain, sinful/criminal behaviors, by people who,
1. do not deserve the truth (because we know that they would use it to hurt us or to hurt others if they knew it .. for instance, I do not believe that Corrie ten Boom sinned when she lied to the Nazi's to protect the Jews who were hiding in her house), or those who,
2. need to understand clearly that we will neither condone nor suffer/sit idly by when they are attempting to harm us, or someone else (I'm referring to the kind of people who hurt others as criminals, people who never hear anything from their victims unless it is heavily laced with profanity, no matter how loudly their victim/victims may be screaming at them).
Apart from those two kinds of criminal behaviors, closely following the dictates of Ephesians 4:29 should keep any Christian free from sin whenever he/she speaks
Ephesians 4
29 Let no unwholesome word proceed from your mouth, but only such a word as is good for edification, according to the need of the moment, that it may give grace to those who hear.
God bless you!
~Deut
p.s. - here is something that Amy Carmichael, missionary to the people/children of India, had to say about this.