mumpsimus \MUHMP-suh-muhs\, noun:
1. Adherence to or persistence in an erroneous use of language, memorization, practice, belief, etc., out of habit or obstinacy.
2. A person who persists in a mistaken expression or practice.
"I profess, my good lady," replied I, "that had any one but you made such a declaration, I should have thought it as capricious as that of the clergyman, who, without vindicating his false reading, preferred, from habit's sake, his old Mumpsimus...
-- Sir Walter Scott, The Talisman
Mr. Burgess, who sticks (I fancy) to his old mumpsimus, thought that the other gentleman might have given the canoe a shove to get it clear of the lock
-- Ronald A. Knox, The Footsteps at the Lock
Mumpsimus comes from a story (perhaps first told by Erasmus) about an illiterate priest who mispronounced a word while reciting the liturgy. The priest refused to change the word, even when he was corrected.
Now we have a word for George W Bush's malaprops. Perfect explanation of his "Nook u lar." Instead of Nuclear. I think his pronounciation was incorporated into the language, so people would be able to say it could be pronounced either way.
I have to say, it still bugs the crap out of me to hear it pronounced that way...jus sayin