- Nonplus is a state of confusion where you don't know what to do, think or say.
An example of nonplus is being told to turn right on Fifth Street while approaching the intersection where North Fifth Street is to the left and South Fifth Street is to the right.
nonplus definition by Webster's New World
Origin: Classical Latin non, not plush plus, more: see plus
nonplus definition by American Heritage Dictionary
transitive verb non·plussed also non·plused, non·plus·sing also non·plus·ing, non·plus·ses also non·plus·es
Origin: From Latin nōn plūs, no more : nōn, not; see non- + plūs, more; see pelə-1 in Indo-European roots.