This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
麎 combines 鹿 (deer) with 辰, but the exact historical development and original meaning are uncertain.
A deer 鹿 with 辰 inside. Since the meaning is unclear, picture a deer marked with the sign of the dragon (辰) — a mysterious creature whose purpose is unknown.
For シン, imagine a deer with a shiny (シン) coat, standing in a forest clearing. The shiny deer helps you remember シン.