It may be an error by the French sans-faon ( "brazen, careless") or by its Castilianized version sanfasón that is already used but not yet in the English dictionary. [Note : There is an online video with an explanation referring to this word - with an accent - and the doppler in the sound of a vehicle passing at high speed; but it is not serious, it is a very berreta attempt to troll some dictionary that in the end indexes it, using ignorant people of the web to repeat it in its various forms , such as the original 'suanfonson'. And since we're at it, see also demigrating. ]
