1. A detailed account or clarification of something that involves many interconnected parts, ideas, or factors that are difficult to understand
The professor's complex explanation of quantum mechanics left most students confused.
A explicação complexa do professor sobre mecânica quântica deixou a maioria dos alunos confusa.
2. An intricate or elaborate description that requires significant mental effort to comprehend
He gave a complex explanation for his absence from the meeting.
Ele deu uma explicação complexa para sua ausência na reunião.