This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
渄 is a rare character combining 氵 (water) with 非. The exact historical development is uncertain, but it likely follows a phono-semantic pattern where 非 contributes the sound and water provides a semantic clue.
The water radical 氵 beside 非 suggests something related to water, but the exact meaning is unclear. Imagine a rare, forgotten water spirit named 渄.
For ヒ, picture a water spirit named Hee (ヒ) splashing in the river: Hee -> ヒ, and the water radical 氵 keeps the scene wet.