An Etymological Dictionary of the German Language/Annotated/hinter

hinter, preposition, from the equivalent Middle High German hinter, hinder, Old High German hintar, preposition, ‘behind’; while Old High German nt is changed regularly into nd in Middle High German, it is frequently retained when -er (i.e., vocal r) follows as an independent syllable; compare Winter, from Old High German wintar, munter, from muntar. In hindern the d has been inserted in the normal way, just as in Middle High German, and earlier Modern High German hinder is found as well as hinter. Gothic hindar, preposition, Anglo-Saxon hinder, properly an accusative neuter of an old comparative in -τερο-ν, Sanscrit tara-m. (of which Anglo-Saxon and Gothic have preserved a superlative in -tama-s, Gothic *hinduma, whence hindumists, ‘outermost,’ Anglo-Saxon hindema, ‘the last’). Compare Old Indian pratarám (comparative of pra), adverb, ‘further, onwards,’ avatarám (allied to preposition ava), adverb, ‘further away,’ vitarám (allied to preposition vi), compare wider. The comparative hinter is used as an adjective in Old High German hintaro, Modern High German hinter, ‘hinder, posterior.’