Lack of power or ability; weakness, helplessness. Also (in early use): lack of means, poverty.
Late Middle English; earliest use found in William Langland (c1325–c1390), poet. From un- + power.
with object To deprive of power. Also (now chiefly): to reduce or stop the supply of power to (a machine, etc.); to power down.
Mid 17th century. From un- + power.