lucidity, be clear, clear, clarify, settle, strain, look grave

澄んだ空気の中で、遠くの山が見える。

In the clear air, you can see distant mountains.

彼の目は澄んでいて、清潔感がある。

His eyes are clear and give a sense of cleanliness.

泥が沈んで、水が澄んだ。

The mud settled and the water became clear.