from Middle Low German weddersins, from Middle High German widersinnes, from wider ‘against’ + sin ‘direction’; the second element was associated with Scots sin ‘sun’

in a direction contrary to the sun's course, considered as unlucky; counterclockwise

She didn't wake as her dad scooped her up in his arms, carried her down the staircase, then turned fully widdershins so that he was facing North.