lucidity, be clear, clear, clarify, settle, strain, look grave
澄 centers on clarity and stillness: a liquid becoming clear and settled, or a person's expression or mind becoming calm and serious. The ideas of straining, clarifying, and looking grave all stem from this core of making something pure and undisturbed.
to become clear (water, air, etc.); to become transparent
clear; serene
primness; putting on airs; prim person
clear layer of fluid (at the top of a mixture); supernatant liquid; supernate
to sharpen; to grind; to whet; to hone; to make keen
primness; putting on airs; prim person
primly; with one's nose in the air; smugly
to affect a serene mood; to affect a serious demeanor; to act prudishly; to assume an air of superiority
to look unconcerned; to assume a composed look
lucid; clear
whirligig beetle (any insect of family Gyrinidae, esp. the Japanese whirligig beetle, Gyrinus japonicus)
clarifying agent; clarificant; clarifier; clearing agent; fining agent
clarified butter
a prim person
to put on airs; to affect (e.g. importance); to look wise
to clear; to make clear
perfectly clear
to be perfectly clear (water, air, etc.); to clear up
to be perfectly clear
limpid water
澄 combines 氵 (water) with 登, which likely contributes the sound and the idea of rising or ascending, together suggesting water that has settled and become clear after disturbance.
Water 氵 plus 登 (climb, ascend) suggests sediment settling and clarity rising to the top. Picture a muddy stream where the dirt slowly sinks and the water becomes clear and calm.
For チョウ, imagine a clear, still pond where a long-serving chief named Chou gazes at his reflection: Chou -> チョウ, and the water is perfectly clear.