An Etymological Dictionary of the German Language/Annotated/aber
aber, adverb and conjunction, ‘but, however,’ from Middle High German aber (aver), abe (ave), adverb and conjunction, ‘again, once more, on the contrary, but’; Old High German abur, avar, adverb and conjunction with both meanings; to this Old High German avarôn. ‘to repeat,’ Modern High German (Upper German) äfern is allied. Compare Gothic afar, preposition, ‘after,’ adverb, ‘afterwards,’ Old Icelandic afar, ‘very,’ in compounds; the word does not occur in Saxon dialects, but its derivative Old Saxon aƀaro, Anglo-Saxon eafora, ‘descendant’ (compare Gothic afar, ‘afterwards’), exists. It is probably related to ab and its cognates; compare further Sanscrit ápara, ‘the later,’ aparám, adverb, ‘latterly, in future,’ aparī̆, ‘future.’
aber, äber, adjective, (Upper German), äfer (Franc), ‘free from snow, laid bare’; from the primary form *âbar, âbiri (âfiri); originally cognate with Latin apricus, ‘sunny.’