This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
庽 combines 广 (building) with 禺, but the exact historical development and original meaning are uncertain.
The kanji has a building 广 enclosing 禺, but its meaning is unclear. Imagine a mysterious building with an unknown purpose.
For グウ, imagine a ghostly 'goo' oozing out of the mysterious building: goo -> グウ, and the strange substance hints at the kanji's obscurity.