Nonplussing [verb]

Peter was puzzled, and scratched his ear like a man at a nonplus.

They were put to a nonplus, and summoned the Devil to their relief.

The inquiring mind is at a nonplus, and is likely to remain so.

This reply seemed to nonplus us all with the exception of Maitland and Godin.

Wingate was now at a nonplus, and “could not well tell what to say.”

Phonny was put quite to a nonplus by this unexpected answer.

The idea at the bottom of the piece is that the devil will carry off the wee boy if he can nonplus him.

Never having been paid such an attention in all my life before, I felt rather at a nonplus.

Nonplus, non′plus, n. a state in which no more can be done or said: great difficulty.

Mr. and Mrs. Accleton were at somewhat of a nonplus as to the most feasible means of procuring the attendance of Sally.