1911 Encyclopædia Britannica/Profanity

PROFANITY, irreverent or blasphemous language, swearing, by the use of words casting derision on sacred or divine things, especially the taking of the name of God in vain (see Blasphemy; and Swearing). The word “profane,” derived from Lat. profanum, outside the temple (fanum), hence opposed to sacrum or religiosum, in the sense of not sacred, common, is used in English not only as meaning irreverent, or blasphemous, but also in the senses of the original Latin, not initiated into sacred mysteries, hence, lay, secular, or as referring to subjects not connected with sacred or biblical matters, e.g. profane literature, history, &c.