mumpsimus

[ muhmp-suh-muh s ]
/ ˈmʌmp sə məs /

noun, plural mump·si·mus·es for 2.

adherence to or persistence in an erroneous use of language, memorization, practice, belief, etc., out of habit or obstinacy (opposed to sumpsimus).
a person who persists in a mistaken expression or practice (opposed to sumpsimus).

Origin of mumpsimus

1520–30; from a story, which perhaps originated with Erasmus, of an illiterate priest who said mumpsimus rather than sūmpsimus (1st plural perfect indicative of Latin sūmere to pick up; see consume) while reciting the liturgy, and refused to change the word when corrected

Example sentences from the Web for mumpsimus