This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
峮 combines 山 (mountain) with 君, which likely contributes the sound. The exact historical development is uncertain.
A mountain 山 with 君 on the right. Since the meaning is unclear, picture a mountain named after a ruler (君), but its purpose is unknown.
For キン, imagine a king (キン) standing on the mountain 山, ruling over the land. King -> キン.