The word "刚愎" is formed by combining the character "刚", meaning hard or rigid, which itself is a pictophonetic character with the radical "刂" (knife) suggesting hardness and "冈" as phonetic, and the character "愎", meaning stubborn, also a pictophonetic character with the radical "忄" (heart) indicating a mental trait and "复" as phonetic; together they create a compound word where "刚" intensifies "愎" to convey obstinate rigidity in character.