where did "bad words" come from? (profanity)?

Bad words are not just bad words. Every word expresses an idea, an item or an action. Any word that names an object or human body organ that you would not, (under normal circumstances) be proud to display in public, is a bad word. So, what is bad is not the word but whatever idea is being expressed by the word. I believe if the mouth as an organ, was not supposed to be displayed in public, eventually the word 'mouth' itself would be vulgar. The word f**k is vulgar because the action it represents is vugar. So, as society developed language through the naming and describing of its surroundings, it created bad words. If the vagina was named 'stick' then, the word stick would have been a bad word even today.