This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
莄 combines the grass radical 艹 with 更, but the exact historical development and original meaning are uncertain.
The grass radical 艹 sits above 更, suggesting a plant or grass-related idea, but the specific meaning is unclear.
For コウ, imagine a coat (コート) hanging on a grass plant: coat -> コウ, and the grass radical 艹 reminds you it's a plant.
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