Nonplus (?), n. [L. non not + plus more, further. See Plural.] A state or condition which baffles reason or confounds judgment; insuperable difficulty; inability to proceed or decide; puzzle; quandary.[1913 Webster]
Both of them are a perfect nonplus and baffle to all human understanding.
Nonplus (?), v. t. [imp. & p. p. Nonplused (?) or Nonplussed; p. pr. & vb. n. Nonplusing or Nonplussing.] To puzzle; to confound; to perplex; to cause to stop by embarrassment.[1913 Webster]
He has been nonplused by Mr. Dry's desiring him to tell what it was that he endeavored to prove.