It is easy to be nonplussed by the word "nonplussed."
It is commonly used as a substitute for "unfazed" or undaunted," although it means perplexed or bewildered.
Surprisingly, there's no entry for nonplussed in The Associated Press Stylebook.
At least not yet.
(But in my experience as a copy editor, or copyeditor, if you prefer, at a newspaper, the sports desk seemed to shun The AP Stylebook about as much as some of its prose stylists shucked modesty and moderation, especially in the Run-Away or Rampant Metaphor Department. I digress.)
Today I saw this sentence in the sports section (called "Sport" [singular] in British papers) of the local paper:
"[name of basketball player] seems nonplussed by the big time."
True, you can't tell what the sense is just by that sentence, but if you read on you understand by context that the intended sense was "unfazed."
I refer you to Charles Hodgson for an enriching and entertaining history of "nonplussed."
I don't deny that words change meaning and would not be surprised to find that perfectly acceptable dictionaries now give variant definitions for nonplussed that incorporate the "right" and the "wrong" meanings.
I don't get my Y-fronts in a knot over these things.
A pedant does reside in my bones, but I also am capable of sitting back and enjoying the etymological ride, so to speak.
(Note to true editors: yes, yes, yes, this post is a mess regarding consistent or proper use of quotation marks and italics. Mea culpa. Mea maxima culpa.)