nonplus \non-PLUS, NON-plus\ (verb tr.) - To put at a loss for what to do, think, or say; perplex. (noun) 0 -A state of perplexity or bewilderment.
"The Native-American Navajo Code Talkers used a code created with their native language to nonplus the Japanese in the Pacific during World War II."
From Latin non plus (no more).