This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The historical origin of 侲 is uncertain. It combines 亻 (person) with 辰, but the exact development is unclear.
A person 亻 beside 辰, a shape associated with the dragon or early morning. Without a clear meaning, treat it as a person linked to an unknown concept.
For シン, imagine a person 亻 standing beside a dragon 辰, and the dragon lets out a sharp shin sound: shin -> シン.