/non plus", non"plus/ , v. , nonplussed or nonplused, nonplussing or nonplusing , n.
v.t.
1. to render utterly perplexed; puzzle completely.
n.
2. a state of utter perplexity.
[ 1575-85; (n.) non plus lit., not more, no further, i.e., a state in which nothing more can be done ]
Syn. 1. perplex, confuse, confound, disconcert.