- to render utterly perplexed by something unexpected; puzzle completely: He nonplussed his questioners by answering in riddles.
- to cause to feel indifferent, calm, or unexcited: The shoppers were entirely nonplussed by the disturbance in the street, continuing to gaze at window displays as they strolled along.
- a state of utter perplexity: When the protagonist's wife suddenly disappears, he's at a nonplus and fights with two different feelings.
- to put at a loss; confound
- a state of utter perplexity prohibiting action or speech
