saliva, spittle, flowing downstream
漦 centers on bodily fluids that flow: saliva, spittle, and by extension the idea of flowing downstream. The meanings connect through the image of liquid moving outward.
漦 is a rare character whose exact historical development is uncertain. It visually contains 水 (water) inside a complex upper structure, which likely relates to the meanings of saliva and flowing liquid, but the origin of the upper components is unclear.
The character has 水 (water) at the bottom, with a tangled upper part that looks like a mouth or face with something dripping down. Picture saliva flowing from the mouth into the water below, or a stream of spittle running downstream.
For ギ, imagine a person with a strong gag reflex producing a lot of saliva: gag -> ギ, and the saliva flows out like the water in 漦.