Code complexity refers to how complicated a piece of software code is, which can affect its readability, maintainability, and performance. It often arises from factors like the number of lines of code, the use of intricate algorithms, and the interdependencies between different parts of the code. High complexity can make it difficult for developers to understand and modify the code, leading to potential errors and increased development time. There are various metrics to measure code complexity, such as Cyclomatic Complexity and Halstead Complexity. These metrics help developers assess the quality of their code and identify areas that may need simplification. Reducing code complexity is essential for creating efficient, reliable, and easy-to-maintain software.