Q: As I understand it, “ignorance” is a lack of knowledge about something, while “stupidity” is doing something when you know it’s a mistake. I ascribe a sort of willfulness to “stupidity.” Is my view reasonable? Is there a better word for this concept of stupidity?
A: Although the two words are often used interchangeably, standard dictionaries generally define “ignorance” as a lack of knowledge, and “stupidity” as a lack of intelligence.
Merriam-Webster’s Collegiate Dictionary (11th ed.), for example, defines “ignorance” as “a lack of knowledge, understanding, or education,” and “stupidity” as “the state of being foolish or unintelligent.”
Most of the five dictionaries we checked (including Merriam-Webster’s) add that “stupidity” can refer to a foolish action as well as foolishness, but we could find only one dictionary that defines the two terms somewhat as you do.
Oxford Dictionaries online says “ignorance” is “lack of knowledge or information,” while “stupidity” is “behavior that shows a lack of good sense or judgment” or “the quality of being stupid or unintelligent.”
You could perhaps defend your view as reasonable by citing Oxford, but we think it would be more sensible to go with the majority on this. The point of language is communicating. Why choose a usage that may be misunderstood?
Is there a better word, you ask, for the quality that leads to willfully doing something stupid?
Well, words like “imprudence,” “incompetence,” and “ineptitude” come to mind, though none of them clearly indicate willfulness. “Rashness” and “recklessness” suggest willfulness but not necessarily lack of intelligence.
Etymology doesn’t help us here. When “ignorance” and “stupidity” showed up in English, they meant pretty much the same as they do today.
English borrowed the word “ignorance” from the Old French ignorance, according to the Oxford English Dictionary, but the ultimate source is ignorantia, Latin for lack of knowledge.
When the word first showed up in Middle English in the early 13th century, the OED says, it meant “the fact or condition of being ignorant; want of knowledge (general or special).”
The earliest Oxford example is from the Ancrene Riwle (circa 1225), an anonymous guide for monastic women: “Sunne & ignorance. þet [is] vnwisdom & unweotenesse” (“Sin & ignorance. That is, unwisdom and unwitnessing”).
As for “stupidity,” English adapted it in the 16th century from stupiditas, Latin for dullness or senselessness. The ultimate source is the verb stupere (to be stunned or benumbed), which also gave us the word “stupor.”
When “stupidity” first appeared, according to the OED, it meant “dullness or slowness of apprehension; gross want of intelligence.”
The dictionary’s earliest citation is from Robert Copeland’s 1542 translation of a medical treatise by the French surgeon Guy de Chauliac:
“Nowe we must esteme the stupydyte or audacyte of the man. I say the stupidite yf he thynke to say well, and the boldnes yf he fele hym selfe culpable to saye nothynge.”
And here’s a shorter and wittier example from Every Man in his Humor, a 1598 play by Ben Jonson: “I forgiue Mr. Stephen, for he is stupiditie it selfe!”
We’re sorry to disappoint you, but none of the senses for “stupidity” in the OED suggest willfulness.
However, an obsolete sense that’s not applicable got our attention: numbness, as in “stupidity of the teeth,” an English version of a late Latin expression, stupor dentium.