nonplussed means unsure how to act or respond; bewildered, perplexed.
nonplussed is pronounced /nɒnˈplʌst/.
Why “nonplussed” is a great word
A state of being so bewildered that one cannot proceed, think, or speak. From the Latin nōn plūs (“no further, no more”), from nōn (“not”) + plūs (“more, further”), first recorded in English c. 1600. Unlike “unfazed” (which implies calm composure) or “flummoxed” (which suggests pure confusion), “nonplussed” denotes the specific paralysis of being brought to a full stop. It is the host who opens the door to find not one guest but fifty, the witness who forgets her own name under cross-examination, the reader who turns the page and discovers the novel has ended mid-sentence—each stranded in the hollow pause where comprehension outruns reaction, a quiet, personal terminus where all possible roads seem to have vanished.
Etymology
From nonplus (“state of bewilderment or perplexity”, noun) or nonplus (“to bewilder or perplex (someone)”, verb) + -ed (suffix forming adjectives, and the past tense and past participle forms of verbs). Nonplus (noun) is derived from Latin nōn plūs (“no further, no more”), from nōn (“not”) + plūs (“additionally, more; further”) (ultimately from Proto-Indo-European *pleh₁- (“to fill”)). The etymological sense is similar to being left speechless as a result of confusion: the nonplussed person can say or do “no more”.
Adjective sense 2 (“unaffected”) is probably from a misinterpretation of the first element of the word as the prefix non- meaning “not”.
adj
- Unsure how to act or respond; bewildered, perplexed.“[N]ote the honeſt Quaker vvas nonpluſſed, and greatly ſurprized at that Queſtion.”
- Unaffected, unfazed; unimpressed.“"I regard Dean [W. P.] Baddeley's gambling activities with embarrassment and dismay," said Anglican dean of Melbourne S. Barton Babbage. […] The Rev. Baddeley remained nonplussed. "I don't intend to make a habit of going to the races but I feel clergymen should mix as our Lord did with all walks of life," Dr. Baddeley said.”
Words closest in meaning
By meaning, not spelling — each word's AI semantic fingerprint, nearest first.
- nonplus 94% match — A state of bewilderment or perplexity. vs nonplussed →
- bewildered 87% match — Baffled, confused, mystified, at a loss, not thinking clearly, or uncertain. vs nonplussed →
- bewilder 86% match — To confuse, disorientate, or puzzle someone, especially with many different choices. vs nonplussed →
- consternation 85% match — Amazement or horror that confounds the faculties, and incapacitates for reflection; terror, combined with amazement; dismay. vs nonplussed →
- perplexity 85% match — The state or quality of being perplexed. vs nonplussed →
- stupefaction 85% match — The state of extreme shock or astonishment. vs nonplussed →
- quandary 85% match — A state of not knowing what to decide; a state of difficulty or perplexity; a state of uncertainty, hesitation or puzzlement. vs nonplussed →
- bafflement 85% match — The result or state of being baffled, confused, or puzzled; a shocked feeling of perplexed bewilderment, caused by being utterly unable to understand something or to move on from one's incomprehension. vs nonplussed →