Word of the Day: Mumpsimus

Some words feel as though they were coined to describe human nature perfectly. Mumpsimus is one of them. It captures that all-too-familiar tendency to cling to an old belief or habit, even after it’s been clearly shown to be wrong, simply because “that’s how it’s always been done.”

What Does “Mumpsimus” Mean?

A mumpsimus is a person who stubbornly adheres to a proven error, often out of habit, pride, or resistance to change. The word also refers to the belief or custom itself—a practice that continues even after its falsehood has been exposed.


In simpler terms, mumpsimus describes someone who refuses to update their thinking, even when better information is right in front of them. It’s not mere ignorance; it’s chosen ignorance.

Pronunciation

Pronounced ˈməmps-ə-məs, "mumpsimus" is a sharp, slightly humorous word with a serious message about learning, humility, and the danger of stubborn thinking, as per Merriam Webster.

The Curious Origin of the Word

The origin of "mumpsimus" is one of the most memorable in the English language. It comes from a medieval anecdote involving an illiterate priest who repeatedly mispronounced the Latin word sumpsimus (“we have taken”) during the Catholic Mass.

When corrected, the priest reportedly replied that he would not abandon “his old mumpsimus for the critic’s new sumpsimus.” The mistaken word stuck—and so did its meaning. Over time, mumpsimus came to symbolize any entrenched error that survives purely through stubborn tradition.

The term ultimately traces back to Latin sumere, meaning “to take,” though its enduring power lies in its human story rather than its grammar.

Why Mumpsimus Still Matters Today

Mumpsimus isn’t just a historical curiosity—it’s deeply relevant in modern life. We see it in outdated workplace practices, unchallenged social norms, political dogma, and even personal habits that no longer serve us.

Recognizing mumpsimus encourages intellectual humility. It reminds us that progress depends not just on gaining new knowledge, but on being willing to let go of comfortable mistakes. In science, education, leadership, and relationships, the refusal to question old assumptions can quietly hold everything back.

Usage in Sentences

Though rare, mumpsimus is precise and powerful when used well.

Example sentences:

Clinging to that policy despite clear evidence is pure mumpsimus.

The debate stalled because a few mumpsimuses refused to accept the updated data.

He finally abandoned his old mumpsimus and admitted he’d been wrong.

Synonyms:

Dogmatist, traditionalist, stick-in-the-mud, reactionary, obstinate thinker

FAQs

Is mumpsimus always used negatively?
Yes, generally. It describes stubborn adherence to error, though it can be used humorously or gently in informal contexts.

What is the opposite of mumpsimus?
The opposite is often said to be sciolist or, more loosely, an open-minded or intellectually flexible person willing to revise beliefs.