This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鍑 combines 金 (metal) with 复, which likely contributes the sound. The exact historical development is uncertain.
The metal radical 金 suggests something made of metal, but the overall meaning is unclear. Picture an ancient metal vessel whose purpose has been forgotten.
For フウ, imagine a forgotten metal pot that makes a hollow 'foo' sound when tapped: foo -> フウ.