Etymology

From wither- +‎ shins, sins, alteration of withersuns ‎(“contrary to the sun's course”, literally “against the sun's”), modelled after Middle Low German, weddersins, weddersinnes ‎(“in the opposite direction”), from Middle High German widdersinnes ‎(“in the opposite direction”, literally “contrary to reason”), from wider ‎(“opposite”) + sinnes ‎(genitive of sin ‎(“course”)). Compare also Old English wiþersīenes ‎(“backwards, withershins”), Icelandic viðer ‎(“against”), Danish and Swedish veder. More at wither, sense.