This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鋠 combines 金 (metal) with 辰, which likely contributes the sound. The exact historical development is uncertain, and the character is rare.
The left side 金 suggests metal, and the right side 辰 looks like a container. Picture a mysterious metal object whose purpose is unknown.
For シン, imagine a shiny metal shin guard: shin -> シン, and the metal 金 on the left reinforces the image.