so surprised and confused that you do not know what to do or say
Origin and usage
The adjective nonplussed comes from the largely obsolete noun ‘nonplus’, which originally meant ‘a state in which no more can be said or done’, and later ‘a state of surprise and confusion’. The noun comes from the Latin ‘non plus’ meaning ‘not more’ or ‘no further’ and was first used in the late 16th century. The adjective dates from a couple of decades later. There is also a verb, which is rarely used today.
Nonplussed is one of a large number of adjectives that can be used to show surprise and confusion. If you are nonplussed by something, you are so surprised and confused by it that you are briefly rendered incapable of speech or action. However, a new meaning of nonplussed is creeping into published writing. The other day I read of someone that he ‘seemed nonplussed‘ by having been found in contempt of Parliament and despite the finding had returned to public life without suffering any penalty. The standard meaning of the adjective did not seem to fit either with the context or with what I knew of the incident, and indeed it doesn’t. What the writer wanted to say was that the person was supremely unbothered by the finding and in fact viewed it with indifference – almost the opposite of the standard meaning. Words that might be used here instead include ‘unfazed‘, ‘unperturbed’ or even ‘not fussed‘. This meaning of nonplussed has been around in American English for some decades, despite which the dictionaries that give it refer to it as non-standard and recommend against using it. This is because of the potential for ambiguity that is neatly illustrated by my confusion when I came across it. Despite the claims of sticklers and pedants, ambiguity in real-world writing is comparatively rare, because context makes the meaning clear. Nonplussed is one case where I think the non-standard meaning is best avoided in order not to confuse your readers.
“When I put this to Simon, he is momentarily nonplussed.”
“He spoke rapidly, completely nonplussed by my inability to comprehend.”
“He was attempting to look nonplussed at the discovery, but he failed.”
surprised, confused, bewildered, perplexed