This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
釻 combines 金 (metal) with 丸 (round), but its exact historical development is uncertain.
The kanji visually contains 金 (metal) and 丸 (round), but its meaning is unclear. It may have once referred to a metal object or a type of crossbow, but this is speculative.
For ヒュウ, imagine a rare metal ball (丸) that makes a 'hyuu' sound as it rolls: hyuu -> ヒュウ.