nonplused

From the verb nonplus: (⇒ conjugate)

nonplused is: ⓘ

v past (US)

v past p (US)

WordReference Random House Learner's Dictionary of American English © 2025

non•plus /nɑnˈplʌs, ˈnɑnplʌs/   v. [~ + object] , -plussed or -plused, -plus•sing or -plus•ing. 

1. to make (someone) completely confused, puzzled, or unsure;
   baffle:
   The child was nonplussed by the bright lights.

WordReference Random House Unabridged Dictionary of American English © 2025

non•plus  (non plus′, non′plus), v., -plussed or -plused, -plus•sing or -plus•ing, n. 
v.t. 

1. to render utterly perplexed;
   puzzle completely.

n. 

2. a state of utter perplexity.

• Latin nōn plūs literally, not more, no further, i.e., a state in which nothing more can be done
• (noun, nominal) 1575–85

Synonyms

• 1. perplex, confuse, confound, disconcert.

Collins Concise English Dictionary © HarperCollins Publishers::

nonplus / nɒnˈplʌs/ verb ( -plusses, -plussing, -plussed) ( -pluses, -plusing, -plused)

1. (transitive) to put at a loss; confound

noun ( -pluses)

1. a state of utter perplexity prohibiting action or speech

Etymology: 16th Century: from Latin nōn plūs no further (that is, nothing further can be said or done)