Consisting of interconnected or interwoven parts; composite. Composed of two or more units: a complex carbohydrate. Involved or intricate, as in structure; complicated. Grammar Consisting of at least one bound form. Used of a word. Grammar Consisting of an independent clause and at least one other independent or dependent clause. Used of a sentence. A whole composed of interconnected or interwoven parts: a complex of cities and suburbs; the military-industrial complex. In psychology, a group of related, often repressed ideas and impulses that compel characteristic or habitual patterns of thought, feelings, and behavior. No longer in scientific use. An exaggerated or obsessive concern or fear. Medicine The combination of factors, symptoms, or signs of a disease or disorder that forms a syndrome.