mumpsimus [muhmp-suh-muh s]
noun, plural mumpsimuses for 2.
1. 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 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
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