nonplus

non·plus  (nn-pls)

tr.v. non·plused also non·plussed, non·plus·ing also non·plus·sing, non·plus·es also non·plus·ses

To put at a loss as to what to think, say, or do; bewilder.

n.

A state of perplexity, confusion, or bewilderment.

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[From Latin nn pls, no more : nn, not; see non- + pls, more; see pel-¹ in Indo-European roots.]

Thesaurus

Verb

1.

nonplus - be a mystery or bewildering to; "This beats me!"; "Got me--I don't know the answer!"; "a vexing problem"; "This question really stuck me" bewilder, dumbfound, flummox, baffle, mystify, perplex, puzzle, stupefy, amaze, gravel, vex, pose, stick, beat, get stump, mix up - cause to be perplexed or confounded; "This problem stumped her" befuddle, confound, confuse, discombobulate, fox, bedevil, fuddle, throw - be confusing or perplexing to; cause to be unable to think clearly; "These questions confuse even the experts"; "This question completely threw me"; "This question befuddled even the teacher" riddle - set a difficult problem or riddle; "riddle me a riddle" elude, escape - be incomprehensible to; escape understanding by; "What you are seeing in him eludes me"