疾

A phono-semantic compound, consisting of:

疒 (“illness, sickness”) as the semantic element;

矢 (“arrow”) as the phonetic element.

질병 (疾病) – disease, illness

질환 (疾患) – disease, disorder

질주 (疾走) – dash, sprint

질풍 (疾風) – storm wind, tempest

질투 (嫉妬, lit. “illness of envy”) – jealousy, envy

Here, 疾 conveys both the literal sense of illness and the figurative sense of swiftness or intensity.

An ancient form 𠥻 exists, which is visually similar to 廿. The difference is that in 𠥻, the bottom stroke connects with the left vertical stroke, while in 廿 they are written separately.