What characteristic does a circular definition lack?

A circular definition lacks clear differentiation of terms because it essentially defines a concept using the same concept or closely related terms, which does not provide any new information or clarification. For example, defining a "car" as a "vehicle that you drive" does not give a precise understanding of what constitutes a car since "vehicle" can include many types of transportation. This results in a lack of specificity and clarity, making it difficult for someone to understand the term being defined accurately. Circular definitions fail to elucidate the unique characteristics or attributes of a term, leading to confusion rather than a clear understanding.

In contrast, while other characteristics like creativity, reference to old meanings, or complexity could be relevant in different contexts, they are not fundamental issues that arise specifically from the nature of circular definitions. The core problem remains the confusion caused by the overlap in the definitions used.