mumpsimus

Etymology

Malapropism of Latin sumpsimus, form of sūmō (“to take”), from a story of an old monk who misrecited the Eucharist with quod in ōre mumpsimus instead of quod in ōre sumpsimus “which we have taken into the mouth”, and stubbornly continued using the incorrect form even after being corrected. Attested 1530 in The Practice of Prelates by William Tyndale, variously attributed to Richard Pace (1517) or Desiderius Erasmus.