The Chinese word **疑心** (yíxīn), meaning "suspicion" or "doubt," is a compound formed through the combination of two meaningful characters: **疑** (yí), which means "to doubt" or "to suspect," and **心** (xīn), which means "heart" or "mind." In Chinese word formation, this is an example of a **coordinative or endocentric compound**, where the two elements together create a new, more specific meaning than either character alone. Here, **疑** provides the core concept of doubt, while **心** specifies the locus or faculty—the mind or heart—from which this doubt originates, effectively forming the concept of a "doubting mind" or "suspicious heart." This structural pattern is highly productive in Chinese, allowing for the logical and intuitive creation of abstract nouns from simpler, concrete semantic components.