This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
腧 combines the flesh radical ⺼ with the phonetic component 俞. The exact historical development and original meaning are uncertain.
The flesh radical ⺼ suggests a body part, but without a clear meaning, picture a mysterious body part labeled with the sound 俞. Its meaning remains unknown.
For シュ, imagine a shoe (シュ) shaped like the flesh radical ⺼, but it's an odd, unknown body part shoe. The shoe sound cues シュ.