What does "sumpsimus" mean?

Adherence to or persistence in using a strictly correct term in rejection of a more common (but technically incorrect) form.

Sumpsimus

Common synonyms include: conservative grammarian, error, incorrect form, linguistic purist, misusage, pedant.

noun

noun ·Rare ·Advanced level

Noun

1
Adherence to or persistence in using a strictly correct term in rejection of a more common (but technically incorrect) form. countable, uncountable
"I'll not change my old mumpsimus for your new sumpsimus!"
2
a correct expression that takes the place of a popular but incorrect expression wordnet
3
A person obstinate or zealous about such correctness; a pedant. countable, uncountable

"I'll not change my old mumpsimus for your new sumpsimus!"

From Latin sumpsimus, c. 1540–50.