素早い
すばやい · subayai · JLPT N1 · i-adj
fast; quick
🐆 素早い = 素 (immediate) + 早い (fast): an instantly quick, cheetah-like speed
早い means fast or early. The prefix 素 adds a sense of immediacy, as in 素早く (promptly, without delay). Together they describe quickness of action, like a cheetah's sprint.
素 — silk 糸 + sheng 𠂹 (hanging threads)
Originally depicted raw, undyed silk hanging to dry, with the silk radical 糸 below and strands above. From this came the meaning 'plain, unadorned, white,' then extended to 'basic element' or 'plain/simple' in general. The 'vegetarian' sense developed later from the idea of plain, unembellished food.
早 — sun 日 + ten 十 (originally 甲, a helmet/sprout)
Originally depicted the sun 日 rising above a sprouting plant or a person's head, suggesting the early morning when the sun first appears. The lower component was simplified over time into 十. The core meaning 'morning, early' has remained stable since oracle bone script.