The word "惶恐" is formed by combining two characters that each convey fear. "惶" consists of the heart/mind radical "忄" and the phonetic component "皇", denoting a state of fearfulness. "恐" includes the heart/mind radical "心" with the component "巩" providing phonetic cues, meaning dread or terror. Together, they reinforce each other to express intense apprehension or fright.