This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
貙 combines the beast radical 豸 with 區, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side 豸 suggests a beast or animal. The right side 區 looks like a container or region. Imagine a mysterious creature kept in an enclosure, but its exact nature is unknown.
For チュ, imagine a beast making a soft 'chew' sound as it gnaws inside its enclosure: chew -> チュ.