Clara comes directly from the Latin clarus, meaning bright or clear, and the name is traditionally associated with clarity of both light and thought. It's often read as suggesting straightforwardness -- someone whose intentions are legible rather than obscured, luminous in a plain, unaffected sense rather than a dazzling one.
The Superior Planets are most efficacious; the inferiour are weak, and easily do suffer by the Superiours, and receive good or ill from them. - William Lilly (1602.-1681.)