This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
瀗 combines 氵 (water) with 憲, but the exact historical development and original meaning are uncertain. It may have been a phono-semantic compound, but no clear semantic connection is known.
The water radical 氵 beside 憲 suggests something related to water, but without a clear meaning, picture a mysterious ancient character whose meaning has been lost like water under a bridge.
For ケン, imagine a wise man named Ken who studies rare kanji: Ken -> ケン, and he puzzles over the water-like shape of 瀗.
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