This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
漄 combines 氵 (water) with 崖 (cliff). The exact historical development is uncertain, but it likely relates to water at the edge or shore.
Water 氵 beside a cliff 崖 suggests a shoreline or water's edge, but the exact meaning is unclear.
For ガイ, imagine a guy standing at the water's edge by a cliff: guy -> ガイ.