eminent, lofty, beautiful, surname
卲 centers on elevated distinction: someone eminent, lofty, or beautiful in a refined sense. The surname use is a natural extension of a name meaning 'high' or 'noble'.
卲 is a rare character. It likely combines 召 (which may contribute sound) with 卩 (a kneeling person), but the exact historical development is uncertain.
The left side 召 looks like a call to rise, and the right side 卩 is a kneeling person. Imagine someone being called to stand up and become eminent and lofty.
For ショウ, picture a show where an eminent person is called to the stage: show -> ショウ, and the person rises to a lofty position.