The word "惶恐不安" is formed by concatenating two two-character compounds: "惶恐", meaning fearful or terrified, and "不安", meaning not calm or uneasy. Each character contributes directly to the meaning, "惶" and "恐" both denote fear, while "不" negates "安" (peaceful), resulting in a reinforced expression of intense anxiety through the juxtaposition of similar concepts.