寞

roof (宀) + [sound: mò] (莫) = lonesome stillness inside

The roof radical suggests an enclosed, interior space — a room where no one stirs. 莫 mainly lends the mò sound; the stillness of that empty dwelling carries the emotional weight.

他一个人住，心里感到很寂寞。

朋友们都走了，她突然觉得落寞起来。