quiet
閴 centers on stillness and silence: a quiet, hushed state. The meaning 'quiet' covers both the absence of noise and a subdued, solitary atmosphere.
閴 combines 門 (gate) with 貝 (shell). The exact historical development is uncertain, but it likely expresses quietness through the image of a secluded gate or a shell-like stillness.
A gate 門 with a shell 貝 inside: imagine a heavy gate closing over a silent, empty courtyard, as quiet as a shell held to the ear.
For ケキ, picture a quiet gate that makes a soft 'keki' sound when it shuts: keki -> ケキ, and the silence returns.