poor, impoverished
寠 centers on a state of severe lack: being poor, impoverished, or worn down by hardship. The meanings of being small or emaciated extend naturally from that core idea of deprivation.
寠 combines 宀 (roof, house) with 婁, which likely contributes the sound and may relate to the idea of being bound or constrained, suggesting a household in poverty. The exact historical development is uncertain.
Under a roof 宀, the complex lower part 婁 looks like a person tangled in hardship, with a woman 女 and something like a tied bundle. Picture a household so poor that its members are worn thin and small.
For ク, imagine a poor person living in a tiny, cramped room that feels like a cube: cube -> ク, and the cube-shaped space reflects their impoverished, confined life.