The kanji 疾 (shitsu) primarily conveys the meaning of "rapid," "quick," "swift," or "sudden." It can also refer to "illness," "disease," or "pain" that comes on quickly or unexpectedly. The core idea revolves around speed, abruptness, and sometimes, a negative connotation of something unwelcome or problematic arising rapidly.

・On-yomi (音読み): シツ (shitsu) ・Kun-yomi (訓読み): はや-い (haya-i) - fast, quick

⚫︎疾走 Translation: Sprinting; dashing. ⚫︎疾病 Translation: Illness; disease. ⚫︎疾風 Translation: Gale; strong wind.

The kanji 疾 is a 形声文字 (keisei moji), a phono-semantic compound. It is composed of the radical 疒 (やまいだれ, yamai-dare) at the top, which signifies "sickness" or "disease," and the phonetic component 矢 (ya), which means "arrow." The combination suggests a disease that strikes as quickly as an arrow. This emphasizes the meaning of suddenness or swiftness in the context of illness.