This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 爯 is uncertain. It visually combines 爫 (claw/hand) and 冉, but the original meaning and component relationships are unclear.
Since the meaning is unclear, focus on the shape: a claw 爫 over 冉, like a hand reaching over something.
For ショウ, imagine a show where a hand 爫 reaches over a mysterious object 冉: show -> ショウ.