adherence to or persistence in an erroneous use of language, memorization, practice, belief, etc., out of habit or obstinacy (opposed to sumpsimus).
2.
a person who persists in a mistaken expression or practice (opposed to sumpsimus).
Origin: 1520–30; from a story, which perh. originated with Erasmus, of an illiterate priest who said mumpsimus rather than sūmpsimus (1st pl. perfect indic. of L sūmere to pick up; see consume) while reciting the liturgy, and refused to change the word when corrected
a traditional notion that is obstinately held although it is unreasonable; "he still holds to the old mumpsimus that a woman's place is in the kitchen"
[muhmp-suh-muh
s] 