fornicating unlawful cardinal knowledge: its use came around
in the early years of
the French revolution. It was written on the walls of the Bastille, before the French
bourgeoisie tore it down.
In today's culture, it can mean a variety of things, such as replacing other words when one is inarticulate, or often referring to its verb form, to have sex with someone. It can also be used as an adjective with negative or positive connotation.