complication

(noun) the act or process of complicating.

(noun) a situation or condition that is complex or confused. Example: "Her coming was a serious complication."

(noun) any disease or disorder that occurs during the course of (or because of) another disease. Example: "Bed sores are a common complication in cases of paralysis."

(noun) a development that complicates a situation. Synonyms: ramification. Example: "The court's decision had many unforeseen ramifications."

(noun) puzzling complexity. Synonyms: complicatedness, knottiness, tortuousness.