澄

Word usually written using kana alone

whirligig beetle (any insect of family Gyrinidae, esp. the Japanese whirligig beetle, Gyrinus japonicus)

pond skater; water strider

to affect a serene mood; to affect a serious demeanor; to act prudishly; to assume an air of superiority

clarified butter

a prim person

Noun or verb acting prenominally

perfectly clear

perfectly clear and serene sky

perfectly clear mirror

perfectly clear mirror