An Etymological Dictionary of the German Language/Annotated/Affe
Affe, masculine, ‘ape, monkey,’ from the equivalent Middle High German affe, Old High German affo, masculine; also in Old High German the feminine forms affa, affin, affinna, ‘female ape.’ A word common to the Teutonic group, unrecorded by chance in Gothic alone, in which, by inference from Old Icelandic ape, Anglo-Saxon apa, English ape (whence Irish and Gaelic apa), Dutch aap, the form must have been *apa. Facts and not linguistic reasons lead to the conclusion that apan- is a primitive loanword with which Old Russian opica, Old Bohemian opice, is connected, and through commercial intercourse reached the Teutons by some unknown route. On account of the assonance it is very often referred, without sufficient reason, to Sanscrit kapi (Greek κῆπος), ‘ape’; at all events, it is certain that no word for Affe common to the Aryan, or even to the West Aryan, group does exist.