通り掛かる
とおりかかる · toorikakaru · JLPT N2 · noun
to happen to pass by
🛣️ 通る (pass through) + 掛かる (come upon) = happen to pass by
通り is the stem of 通る (to pass through). 掛かる (to come upon, to reach) adds the sense of arriving at a place by chance. Together they mean passing a place by accident.
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'.