透き通る
すきとおる · sukitooru · JLPT N2 · verb-godan
to be(come) transparent
🪟 透き (gap) + 通る (pass through) = light passes through the gaps: see-through
透く means to be thin or have gaps so light shows through, and 通る means to pass through. Together they describe something clear enough for light to pass straight through.
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.'
通 — 辵 (辶) walk + 甬 yǒng (phonetic)
通 is a semantic-phonetic compound. The 辶 (chuò) component means 'walk' or 'movement', giving the meaning of going through or passing. 甬 (yǒng), originally depicting a hanging bell or a path, supplies the sound. Together they convey 'to pass through, communicate, connect'.