What is the word to describe a (fully competent) translator's inability to translate the exact sense? [duplicate]
Solution 1:
Even the most accomplished of translators can't work miracles: some things are inevitably lost in translation. -- TFD
Of a word or words, having lost or lacking the full subtlety of meaning or significance when translated from the original language to another, especially when done literally. (Usually formulated as "be/get lost in translation.")
My friend tried explaining a few French idioms to me, but I'm afraid they were lost in translation.