noun a correct expression that takes the place of a popular but incorrect expression; `he preferred his erroneous but pleasing mumpsimus to the correct sumpsimus` Found on https://www.encyclo.co.uk/local/20974
adherence to or persistence in using a strictly correct term, holding to a precise practice, etc., as a rejection of an erroneous but more common form (opposed to mumpsimus). · a person who is obstinate or zealous about such strict correctness (opposed to mumpsimus). Found on https://www.infoplease.com/dictionary/sumpsimus