Today's word is:
Mumpsimus [mump-si-mus; pron mump'si-mes]
A view stubbornly held even when shown to be wrong; one holding such a view.
In an old story, it's said that an ignorant priest, knowing the sound of the Latin Mass but not speaking the language, said the meaningless 'mumpsimus' instead of 'sumpsimus.' When corrected, he is said to have replied, "I will not change my old mumpsimus for your new sumpsimus." This learned joke has lasted five centuries in the form of this fine-sounding word.
Sumpsimus, Latin, meaning 'we have received.'
Having then ended his week with his temporary supervisor, nerdfury was asked to comment upon his time with him for coaching feedback. He wrote:
'He's a nice enough guy, and possibly would make a decent supervisor in a more permanent setting, however he needs to no longer ultracrepidate on people's skills, and learn that mumpsimus on his decisions before someone that knows more than him on the subject helps no one.'
Actually, I never wrote that. But I should!