We might call it “cussing” or “cursing,” but it’s interesting to see the different ways the translators translate this unique Greek word (found only in Colossians 3:8) — “shameful speaking,” “obscene language,” “abusive speech,” “obscene talk,” “evil speech,” “foul speaking,” “foul talk,” “foul-mouthed abuse,” “filthy talking,” “filthy language,” “filthy communication,” etc. You get the idea! And, you know exactly the kind of words, phrases and slang that God is describing!
Now, look at what God says (in the various 
translations) to do with such words, phrases, slang, etc. — “put off,” “put away,” “put out of your life,” “put aside,” “rid yourselves of,” “lay aside,” etc.
God says that such language should never come out of the mouth of a Christian — one is wearing the precious name of His Son! Not only should it never come out, “putting it aside” indicates that it should never “enter” your mouth, even if it doesn’t “exit.” Furthermore, God warns, “If anyone…does not bridle his tongue…this one’s religion is useless” (Jas. 1:26).