This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form visually contains 石 at the bottom, but the origin of the upper component is unclear.
The kanji has no clear meaning, but the bottom 石 (stone) suggests a possible connection to rocks or hardness. Without a known meaning, it is best remembered as a rare stone-related character.
For カク, imagine a rare stone that makes a sharp 'kaku' sound when struck: kaku -> カク.
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