This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. It combines 麥 (wheat) with 皮 (skin), but the original meaning and component relationship are unclear.
With 麥 (wheat) and 皮 (skin), imagine wheat bran or husk, which is the outer skin of wheat. This may help remember the reading ふすま (bran).
For フ, picture a wheat field where the wind makes a soft 'fu' sound as it blows over the husks: fu -> フ.
wheat bran