透明
とうめい · toumei · JLPT N2 · na-adj
transparency
🪟 透 = see through + 明 = bright: 透明 = bright enough to see through
透 means penetrate or see through, and 明 means bright or clear. Together they describe light passing cleanly through, so the word covers both see-through and clean.
透 — walk radical 辶 + 秀 (xiù, elegant/phonetic)
透 is a semantic-phonetic compound. The walk radical 辶 suggests movement or passing through, while 秀 supplies the sound. The original sense was 'to pass through' or 'penetrate,' which extended to meanings like 'thoroughly,' 'transparent,' and 'leak through.'