Webster’s dictionary defines profanity as “The quality or state of being profane; the use of profane language: profane language: or an utterance of profane language.” 
How does someone recognize profanity? The word profane literally means “outside the temple.” The term initially identified people or things that were worldly as opposed to religious. Often profanity is used for shock value in expressing anger and humor. The words often are associated with sexuality and filth. Names of the Deity are used to bring additional potency and irreverence to the expressions. 
Proponents of profanity will argue that there are no lists in the Bible that contain the words which are profane. It is true that there is no place in scripture that gives us a list of words that we should not use. The problem however, is not that no list of forbidden words exists, but rather how could there be? Words come and go, and some words become outdated from human speech over time. Also, new words are created all the time! This being true, a “wordlist” could never be totally germane, if it were even possible to assemble such a list in the first place.
Another element to consider is that no simple grouping of letters is intrinsically evil. For instance take “God” and “dog.” These two words have the same letters, yet the meanings attached to the respective arrangements are worlds apart.  Additionally, syllable sounds are also not inherently evil. Some words from other languages sound like profanity in English. However, they are not profanity in the language spoken. Thus, words cannot be intrinsically “bad” by the way the letters are arranged or the way they sound, it must be by some other measure.
This story by Wayne Jackson may give some insight into more clearly distinguishing what is profanity.
“Some years ago I was lecturing in Africa in an environment heavily influenced by the British culture. I referred to a certain military encounter as a “bloody battle.” Later, I was informed that the expression “bloody” – which to me was a perfectly legitimate descriptive – was “profane” to my English-oriented audience. The cultural connotation attached to the adjective made the difference.” 
Words, then, must have a meaning that is extrinsic [originating from outside itself] to their arrangement of letters or sounds. Meaning is given within a language and even within a society. While words have only extrinsic meaning, it cannot be denied that they do have meaning and they are used to communicate ideas or sentiments. Thus the extrinsic meaning is what determines whether a word is acceptable or profane.
This brings a valuable question into frame, who determines which words are profanity and which are not? Interestingly society and Christianity typically agree at this point. Each society decides for itself which words are profane and which are not. I would not have any trouble communicating to someone about a profane word in American society if I called it profanity and then told them the first letter of the word. Most people know which words are profanities and which are not.
As previously mentioned, profane means outside the temple, it also has a secondary definition: to debase by a wrong, unworthy, or vulgar use, and also, not holy because it is unconsecrated, impure, or defiled. 
From these definitions it is clear that profanity is the vulgar or impure use of language. Another example that displays a common knowledge of profanity is that of people not speaking certain words when they are around children and women (or maybe their grandmother). Most people who would use swear words refrain from them when they are around mixed company. They know that they need to watch their tongues around such an impressionable audience. Also, there have been instances in which someone who has been using profanity finds out that the person to whom they are speaking is a pastor they immediately apologize and also cease using the profane words (this has happened to me!). A final illustration is that when a person asks another to stop using profanity around them, they do not ask, “Which words are the profanities?” they simply stop using them.
To sum up what has been said thus far, profanity is the irreverent, impure, or vulgar use of language. They are words that are used to evoke some kind of offense in connection typically with sexuality and filth. Names of the Deity are added to these words to make them especially irreverent and crude. Also, profanity is decided and known by members in a society.
Check out the other posts here:
- Profanity, Introduction
- Profanity, What is it?
- Profanity, What does the Bible say?
- Profanity, Should Christians ever use it?
 Merriam Webster Online Dictionary; available at https://www.merriam-webster.com/dictionary/profanity
 The Ethics and Religious Liberty Commission’s online journal article “Christians and Profanity: What does the Bible say?” available at http://mail.erlc.com/article/christians-and-profanity-what-does-the-bible-say
 Christian Courier “Profanity – A Biblical Assessment;” available at http://www.christiancourier.com/articles/369-profanity-a-biblical-assessment
 Merriam Webster Online Dictionary; available at https://www.merriam-webster.com/dictionary/profane