chronic illness
痼 centers on a long-lasting, hard-to-cure illness: a chronic condition that persists over time.
痼 combines 疒 (sickness) with 固, which likely contributes both the sound コ and the idea of something fixed or stubborn, suggesting an illness that is hard to remove.
The sickness enclosure 疒 surrounds 固 (hard, solid). Picture an illness that has become solid and stuck inside the body, making it chronic.
For コ, imagine a chronic illness that makes you feel like a small child (子, こ) who cannot get better: 子 -> コ, and the stubborn sickness keeps you weak.
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chronic disease