• IPA: /nɒnˈplʌs/

nonplus (plural nonpluses)

1. A state of perplexity or bewilderment.
   • 1603, Michel de Montaigne, chapter 46, in John Florio, transl., The Essayes, […], book I, printed at London: By Val[entine] Simmes for Edward Blount […], OCLC 946730821 ↗:

     altering Vaudemont, to Vallemontanus, and metamorphosing them, by suting them to the Græcian or Latin tongue, we know not what to make of them, and are often at a non-plus.

   • Both of them are a perfect nonplus and baffle to all human understanding.

nonplus (nonplusses, present participle nonplussing; past and past participle nonplussed)

1. (transitive) to perplex or bewilder someone; to confound or flummox

• German: verwirren, verdutzen, verblüffen
• Portuguese: pasmar
• Russian: озадачивать
• Spanish: confundir, desconcertar, perplejar