This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
珿 combines 王 (jade) with 足 (foot/sufficient). The exact historical development is uncertain, and the character is rare in modern Japanese.
The left side is 王 (jade) and the right side is 足 (foot). Without a clear meaning, picture a jade foot ornament, but treat the meaning as uncertain.
For シュク, imagine a jade shoe ornament: shoe -> シュ, and the foot 足 fits inside. The shoe cue helps recall シュク.