This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 檃 is uncertain. It visually contains ⻖ and 木, but the component relationships are unclear.
The left side suggests a mound or hill, and the bottom is a tree. Without a clear meaning, picture a tree on a hill as a placeholder image.
For イン, imagine an inn built from the wood of a tree on a hill: inn -> イン.