This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
墋 combines 土 (earth) with 參, which likely contributes sound. The exact historical development is uncertain.
The left side is earth 土, and the right side is the complex shape 參. Without a clear meaning, picture a rare, obscure character buried in the earth.
For シン, imagine a shin (shin bone) sticking out of the earth: shin -> シン, and the bone is buried in the dirt.