Some people take a perverse delight in sticking to their old ways even when they have been demonstrably proven to have been incorrect. Such a person might be described as a mumpsimus.

According to a story told by Richard Pace, later to become the Dean of St Paul’s Cathedral, a Monk was challenged in 1517 for mangling the phrase “quod in ore sumpsimus” in the Latin version of the Eucharist as “quod in ore mumpsimus”. When pulled up, the monk replied that he had said the passage that way for forty years and would not “change my old Mumpsimus for your new sumpsimus”.

Mumpsimus became a rather recherche way of describing a silly old fool, a stuck in the mud, an obstinate cuss and with this form of behaviour becoming increasingly more evident, it is due a revival, methinks.