An Etymological Dictionary of the German Language/Annotated/bange
bange, adjective and adverb, ‘anxious(ly), uneasy, uneasily,’ from Middle High German and Middle Low German bange, adverb, ‘anxiously,’ and substantive ‘anxiety, care.’ The root is ange, which further appears in Angst; as enge is the corresponding adjective, bange can only be based on the Middle High German adverb ange, Old High German ango, the adverb afterwards becoming an adjective. The b has arisen from the unaccented prefix be (bî), as g in glauben, grade, from ge. See barmherzig, bleiben.