The word "疑虑" is formed by combining the character "疑", meaning doubt or suspicion, with the character "虑", meaning anxiety or concern. "疑" is a pictophonetic character where the semantic element relates to uncertainty, and "虑" is also pictophonetic, incorporating the "heart" radical to indicate a mental state. Together, they create a compound word where the meanings of both characters contribute to the overall sense of misgiving or apprehensive doubt.