Mr Esswis had promptly negotiated an arrangement between himself, the owner of the sprayer and the owner of the sheep, nonplussing the other two farmers by accepting full blame of the straying animal, as long as unpleasantness and paperwork could be avoided.
-- Michel Faber, Under the Skin: A Novel
I told him that to many people she is one of the best sculptors alive, but he seemed nonplussed by the thought.
-- Jed Perl, Eyewitness: Reports from an Art World in Crisis
She had grown a good deal in the last six months, and an amount of thinking had gone on in that young head which would have astonished him greatly could he have known it all, for Rose was one of the children who observe and meditate much, and now and then nonplus their friends by a wise or curious remark.
-- Louisa May Alcott, Eight Cousins
Nonplus is from the Latin non plus, "no more." To be nonplussed is to be at a point where "no more" can be said or done.