Topographic name for someone who lived in a forest clearing, from Middle High German swant (from swenden "to thin out", "make disappear", causative from swinden "to disappear" modern German schwinden.
Habitational name from any of the various places called Schwand or Schwanden, all in southern Germany, named with this element, from Middle High German swant (from swenden "to thin out", "make disappear", causative from swinden "to disappear" modern German schwinden.