untranslatable

adj

1. Not able to be translated.

   “They referred to de Gaulle as a chienlit, a totally untranslatable term that suggests defecation in bed.”

   “This glyph's data contains references to energy conversion or respiration; however, it may also be describing a transformation via some untranslatable process. It pays close attention to mass-energy equivalence, though the ratios are strange.”

   “In translating untranslatable words, there is a need to use a sentence or phrase before the message can be passed across.”

noun

1. A word or phrase that is impossible to translate satisfactorily from one language to another.