This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
溓 combines 氵 (water) with 兼, but the exact historical development and original meaning are uncertain.
The water radical 氵 beside 兼 suggests something related to water, but the specific meaning is unclear.
For レン, imagine a lens (レン) focusing on the water radical 氵 beside 兼, even though the meaning is uncertain.