An Etymological Dictionary of the German Language/Annotated/geschwind
geschwind, adjective and adverb, ‘swift(ly), rapid(ly), quick(ly),’ from geswinde, adjective and adverb, ‘quick(ly), vehement(ly)'; in earlier Modern High German schwinde, Middle High German swinde (swint), ‘powerful, strong, quick.’ In Old High German the adjective is wanting (yet the proper names Amalswind and Adalswind are recorded). The primary meaning is ‘strong’; the development of meaning to ‘quick’ is similar to that of bald; Gothic swinþs, ‘strong, powerful, healthy,’ Old Icelandic svinnr, ‘intelligent,’ Anglo-Saxon swið, ‘strong, violent,’ show various aspects of the primary meaning. The origin of the cognates is obscure; its relation to gesund is dubious.