What does the Bible say about profanity?

For something to be able to be profaned, it needs to be considered holy in the first place. A profanity, then, takes something that should be treated reverently and with care and reduces it to something common, base, or even crude. In speech this is most often associated with taking God's name in vain. Using holy names and titles like "God," "Christ," or "Jesus" (or combining these names with other harsh words) as expressions of anger or as flippant curses takes what should be holy and debases it, profanes it, makes it common or, worse, makes it loathsome. In the past such profanity has been distinguished from tawdry or "barnyard" speech in which words that are not considered polite are used to engage in what is often called "swearing." But to count as a true profanity in the strictest sense a person would not need to speak a word considered crude or indelicate but would take a holy name, object, or word and use it in unholy, non-worshipful ways. Biblically it is also considered a blasphemous profaning of God's name if a person invokes God in any way in order to bolster the credibility of some oath or claim ("I swear to God I am telling the truth!"). Jesus urged that God's names or titles not be used in this way even when a person is speaking the truth (Matthew 5:33-37), much less when they are invoked to prop up a lie.