phrase or expression whose total meaning differs from the
meaning of the individual words. Idioms come from language and generally cannot be translated literally (word for word). Foreign language students must learn them just as they would learn vocabulary words.It is generally accepted that interpreters did not know much about the laws and rules of translation at the dawn of civilization. They did not have enough scientific knowledge, and some writers maintained later that translation was a problem which could never be solved.
"All translation seems to me to be simply an attempt to solve an insoluble problem."
W. von Humboldt