The word profane precedes the word profanity by over a hundred years. It was first used in a 1450 philological journal, where it was spelled prophane. Other spellings since then have included prophain, prophaine, prophan, profeaine, profaine, profan, progayne, and more. Through Old French, the term was borrowed from Latin profanus, which meant "unclean" but also had the more literal definitions of "unholy" or "not religious" (because who doesn't love bashing atheists?). That's composed of the prefix pro-, meaning "before", and fanum, "temple"; the idea was that profane people should not be admitted into temples with more holy worshippers. Pro traces to Proto-Indo-European per, also "before", and fanum (also the root of fanatic) is from PIE dhes, which was used to form religious words.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.