Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb nonplus

1 sense of nonplus

Sense 1
perplex, vex, stick, get, puzzle, mystify, baffle, beat, pose, bewilder, flummox, stupefy, nonplus, gravel, amaze, dumbfound -- (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")
       => confuse, throw, fox, befuddle, fuddle, bedevil, confound, discombobulate -- (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")

Antonyms of adj nonplused

1 sense of nonplused

Sense 1
at a loss (predicate), nonplused, nonplussed, puzzled -- (filled with bewilderment; "at a loss to understand those remarks"; "puzzled that she left without saying goodbye")

INDIRECT (VIA perplexed) -> unperplexed -- (experiencing no difficulty or confusion or bewilderment)

Similarity of adj nonplused

1 sense of nonplused

Sense 1
at a loss (predicate), nonplused, nonplussed, puzzled -- (filled with bewilderment; "at a loss to understand those remarks"; "puzzled that she left without saying goodbye")
       => perplexed (vs. unperplexed) -- (full of difficulty or confusion or bewilderment; "perplexed language"; "perplexed state of the world")