If you’re nonplussed, that initial non- means you must be without something, right? That seems to be why many people in North America have interpreted this mildly odd word in recent decades to mean calm, undisturbed, unfazed, unimpressed or indifferent. In standard English and elsewhere it still means surprised, confused, perplexed or bewildered. Add to this a tendency to spell it with one s and a British reader can often be nonplussed in the old sense when encountering American examples.
When Billboard recently wrote, “She was very nonplussed and was happy to wait in the queue”, we may be sure the sense intended was “unbothered”. Similarly a sports magazine’s “MS Dhoni is popularly known in cricketing circles as ‘Captain Cool’ for his nonplussed demeanour in tense situations” is clear enough. But what about “I’m completely nonplused by most contemporary architecture” which was recently in the Wall Street Journal? What emotion was the writer feeling? His later comments make clear to a puzzled reader that he was unimpressed rather than confused.
Nonplussed is rather odd in its origin. Its first form was as a noun phrase borrowed directly from the classical Latin non plus, not more or no further. As two words it appears first in an epistle by the Jesuit scholar Robert Parsons in 1582. He meant by it a state in which no more can be said or done, in which a person was unable to proceed in speech or action, resulting in perplexity or puzzlement.
Around the same time it became a verb, to nonplus, meaning to bring somebody to a standstill as a result of being perplexed or confused. The adjective nonplussed also soon appeared. In the early nineteenth century, somebody invented nonplussation, the state of being nonplussed, which had a brief period of popularity around the middle of the century but is now obsolete.