An Etymological Dictionary of the German Language/Annotated/Zwerg
Zwerg, masculine, ‘dwarf, pigmy,’ from the equivalent Middle High German twërc(g), getwërc (also querch, zwërch), Old High German twërg, masculine; a common Teutonic word. Compare Dutch dwerg, Anglo-Saxon dweorh, English dwarf, Old Icelandic dvergr, masculine, Swedish and Danish dverg. The Teutonic base is dwergo-, which is perhaps also connected with the Teutonic root drug, ‘to deceive’; hence Zwerg means literally ‘phantom, illusion’?.