Pronunciation: (sump'su-mus), [key]
—pl. -mus•es for 2.
1. 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).
2. a person who is obstinate or zealous about such strict correctness (opposed to mumpsimus).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.