This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 儵 is uncertain. It visually combines 攸 and 黑, but the original semantic and phonetic roles are unclear.
The kanji has no clear meaning, but visually it looks like a person (攸) surrounded by darkness (黑), perhaps suggesting something fleeting or swift.
For シュウ, imagine a shoe (シュウ) disappearing quickly into the dark (黑) as the person (攸) runs away.