What is the closest meaning of "complexity"?

The term "complexity" refers to the state of being intricate or complicated, involving many interconnected parts or elements. This aligns closely with "intricacy," which signifies a level of detail and elaborateness in a system or structure. When something is described as complex, it often implies that it requires careful thought or consideration due to its multifaceted nature.

In contrast, "simplicity," "ease," and "clarity" suggest a lack of complications or straightforwardness, which are the opposite of complexity. Therefore, "intricacy" is the most fitting synonym for "complexity," as it captures the essence of being elaborate and not easily understood at a glance.