Well, I hate to tell you (no, I don’t) but if that’s what you think being nonplussed means, you’ve got it wrong. On the other hand, maybe you think that that interpretation is just fine, because you subscribe to the descriptivist school that says: “Let’s let the language be determined by semiliterate knuckle-draggers, as long as there are enough of them, and they possess the ‘credentials’ to satisfy the OED.”
According to Merriam-Webster Unabridged, nonplussed means: “to cause to be at a loss as to what to say, think, or do: reduce to a state of total incapacity to act or decide: perplex, baffle, stump.” And that’s the only definition given. And they’ve got it right. Close the book. That’s it, that’s the definition that counts, the one that has been around for a hell of a long time.
“Nonplus” comes from the classical Latin non plus—not more, no further. From that arises the adjective “nonplussed.” The meaning, then, is clear. Right?
Ah, but wait. The OED (once the bible of received standard English) has two definitions for nonplussed:
1. Brought to a nonplus or standstill; at a nonplus; perplexed, confounded.
2. orig. and chiefly U.S. Not disconcerted; unperturbed, unfazed. This usage is often regarded as erroneous: (my boldface).
Now, there’s nothing wrong with putting such an entry as No. 2 in the dictionary, but it should be used to point out not that the usage is merely “regarded” as erroneous, but rather that it is erroneous. In other words, it should be in there as a word to the wise: “Don’t use the word this way, because it’s wrong.” But the descriptivists don’t work that way. Their idea is that meaning should be determined by what most, or at least many, people think the word means. Eventually, after a couple of generations of “educated” people have become accustomed to the word’s meaning something that it didn’t mean in the past—even if that meaning is the opposite of what it originally meant—the descriptivist dictionaries will accept the new meaning as legitimate.
That’s not always the case. If the usage is widely known to be incorrect, it won’t be permitted entry as legitimate no matter how many people erroneously use it. In the case of “irregardless,” for instance, the word does appear in the OED, but it’s simply described as “nonstandard.”
But as we get dumber and dumber (more digital), dictionaries are being replaced by Google, and it was the Google entry that prompted this little screed. If you Google (that use of the word as a verb I think is fine, by the way) “nonplussed,” you get this:
1. (of a person) surprised and confused so much that they are unsure how to react. “he would be completely nonplussed and embarrassed at the idea”
NORTH AMERICAN informal (of a person) not disconcerted; unperturbed
In case you didn’t notice, those meanings contradict one another: like the two entries in the OED, they’re opposites. Sure, Google describes the usage as “informal,” but many of the millions of Google users aren’t going to recognize that as indicating that the usage is nonstandard and unacceptable to decent, upstanding, right-thinking people who don’t move their lips when they read on the subway.
Given that “nonplussed” isn’t a word in common use, most people will have to look it up to know what it means, and when enough of them decide they prefer the incorrect meaning, look for it in the not-too-distant future in dictionaries far and wide and certainly in Google to be defined as “not disconcerted; unperturbed,” with “perplexed, confounded” as secondary meanings, and eventually with the designation “obs.” In case you’re nonplussed (or not) about that abbreviation, it stands for “obsolete.”
Gee ain’t it wonderful how the language evolves, collapses, disintegrates, rots, crumbles, withers and dies. Ah well, we’ll all soon be reduced to BTW and LOL.