This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
礀 combines 石 (stone) with 閒, which likely contributes the sound. The exact historical development is uncertain.
With 石 (stone) on the left and 閒 on the right, picture a stone hidden in a gap or crevice, but its meaning remains unclear.
For カン, imagine a can made of stone sitting in a gap: can -> カン, though the kanji's meaning is uncertain.