Reducing the amount of weight on the skis to manipulate and control pressure. There are four ways to 'unweight':
Turning a ski by taking weight off it. An unweighting movement is generally executed by pivoting the tails of the skis around the tips although occasionally a ski can be pivoted around the centre (as in the Wedel turn or learning in the bumps).
Taking weight off the ski, usually prior to a turn.
Reducing the downward pressure on skis or snowboards in order to facilitate a turn.