The word "孤独" is formed by combining two characters: "孤" and "独". "孤" is composed of the radical "子" (child) and the phonetic component "瓜" (guā), which together convey the meaning of being orphaned or alone. "独" is composed of the radical "犭" (dog) and the phonetic component "虫" (chóng), indicating a solitary or alone meaning. When combined, these characters create a compound word where each contributes a similar semantic sense, resulting in the overall meaning of loneliness or solitude.