- 1made of many different things or parts that are connected; difficult to understand synonym complicated complex machinery the complex structure of the human brain a complex road system a complex argument/problem/subject
- 2(grammar) (of a word or sentence) containing one main part (= the root of a word or main clause of a sentence) and one or more other parts (calledaffixsubordinate clause) In the complex sentence, “I'd like to go the beach, if it's warm enough,” “I'd like to go to the beach” is the main clause, and “if it's warm enough” is the subordinate clause. compare compound
Check pronunciation: complex