complication

This term carries a sense of an unexpected or unwelcome addition to a situation. It suggests that a process was already underway and has now been diverted or hindered by a new, problematic element. It is frequently used in professional, legal, and medical settings to describe an obstacle that requires a change in strategy. When referring to a state of being, it describes a structural density or intricacy. While complexity often describes the inherent nature of a system, complication often implies a level of difficulty that makes a system hard to navigate or resolve, leaning toward a more negative or frustrating connotation.