[Editor’s note: The one asking is Russian, which will explain some of the awkward wording below. The intent of the question is fairly clear]
For the sake of developing an answer, let me assume that you want me to interpret and apply Ephesians 5:4 “Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving.” And let me add Ephesians 4:29 “Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen.”
Many of us desire a set of “rules” to come from these passages, but I believe that human-created rules are, generally, not helpful (Colossians 2:23). For example, we can create a certain list of words that are always sinful to say for any Christian in all situations. I am sure there is a list in Russian, as there is in English. I do not know about Russian, but there are certain words in English which are so profane–so obscene–that they simply should not be used by a Christian in any setting at all. But in English, as I assume in Russian, there is another list of words which are more in the grey area. Here is the reality: What is obscene is malleable. To one group it is obscene and to another it is in a grey area. And the list changes over time. In the US the “n-word” can be spoken by African Americans among themselves and it is not obscene, but in an all-white or mixed crowd it is so offensive that a Christian should not use it. But there will be another context in which we are speaking not about the people, but about the word itself in an analytical sense and then it is not obscene. For the gray-areas words, context is very important. Let me give another example. In the UK, the word “bloody” is considered profane in many settings and I am sure British disciples are asked not to say that word, but in the US, this word has no bad implications at all. I am sure there are in-between situations. Another word in the US which has changed is the word crap. For my generation this word was definitely profane. For the younger generation it is not at all, and they laugh at older people who get upset about the word. What this means to me is that in a younger crowd, depending on the tone I use, I can say the word without a problem, but if I use it with an older crowd, if I use the word at all, I say it softly and let the audience know I am not using it to offend. Either that or not use the word at all.
Here is the bottom line: Although there will clearly be a rather short list of truly obscene words which should not be used by any believer in any public setting, that list is fairly short, and the list of marginal, grey-area words is longer. Therefore, it is better to apply a principle rather than a rule. Here is the principle. If a word or a statement can be reasonably seen to be “unwholesome” (quoting Ephesians 4:29) or if in the particular setting it would be considered “obscene” or “coarse joking” then such a thing ought not to be said. As mature people, we need to understand that making rules is not helpful, but having a loving, sensitive, caring, unselfish attitude is helpful.
The examples you give are helpful. It is possible (but perhaps unlikely) that in a smaller conversation among friends to call someone an intelligent rotten apple might not be obscene or unwholesome, but in another situation (presumably most situations!), it would not be appropriate. I believe that a faithful Christian ought to stay away from the gray areas. In other words, even if what is said might be considered unwholesome or obscene, even by a minority, then the Christian ought to find another way to say it. We should not get as close to sinning as possible, without stepping over the line. But let me say it again. Rules are not helpful. Principles and an unselfish attitude are.
You ask if motives ought to be taken into account. I say not really. Here is why. The statements in Ephesians are not about the motives of the one speaking. The statements are about the effect what we say has on other people. In other words, if I have a good intent, but say something another considers obscene and unwholesome, then I ought not to say it–regardless of my motives. The statements in Ephesians are talking about the effect on others, not on the intent of the speaker. Therefore, saying that we did not have evil intent is not particularly relevant in this case. We need to ask, not whether we intended to offend someone, but whether others were offended. It is not about us. It is about others.
These passages bring up another area, which is “foolish talk” and “coarse joking.” These things could happen without the use of any profane or obscene words at all. We need to be aware, not just of the specific words we use, but of the tone in which we use them. We should be careful not to put people down, talk about sexual things in a loose manner, and generally be always thoughtful about the effect what we say will have on other people. What is appropriate depends a lot on who is hearing, so, again, rules are not very helpful, but all disciples need to be aware that “With the tongue we praise our Lord and Father, and with it we curse human beings, who have been made in God’s likeness. Out of the same mouth come praise and cursing. My brothers and sisters, this should not be! (James 3:9-10). All Christians ought to keep a tight control over their tongue. We should use language that is “pure, peace-loving, considerate, submissive, full of mercy and good fruit, impartial and sincere.” (James 3:17). If we do this, then we will not need rules about what is profane.