nonplus
UK: nɒnˈplʌs | US: nɑːnˈplʌs
vt. to cause someone to be so surprised or confused that they are unsure how to react
n. a state of perplexity or bewilderment
Derived from Latin non plus ("no more"), the word originally described a point where no further progress could be made. By the late 16th century, it evolved to signify a mental state of being unable to proceed due to confusion or surprise. The morpheme non preserves its Latin negation meaning, while plus retains its association with quantity or advancement. The fusion reflects a logical shift from literal stagnation to figurative perplexity.
The unexpected question nonplussed the speaker.
She was in a state of nonplus after hearing the contradictory instructions.
His abrupt resignation left the team nonplussed.
The riddle's complexity nonplussed even the brightest students.
Their silence indicated complete nonplus.