This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
韄 combines 革 (leather) with 蒦, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side 革 suggests leather, and the right side 蒦 is a complex shape. Without a clear meaning, picture a mysterious leather object with an elaborate design.
For アク, imagine an 'act' of crafting a mysterious leather item: act -> アク, tying the sound to the leather radical.