When we talk about the word "un-complex," it indicates something that is easy, straightforward, and uncomplicated. Therefore, the antonyms for un-complex would be complex, intricate, and convoluted. When something is complex, it means it is composed of interconnected parts that make it difficult to understand. Similarly, an intricate situation is delicate and detailed. Lastly, convoluted refers to something that is excessively complicated or twisted. Therefore, using the antonyms of un-complex in a sentence would convey the opposite meaning to what un-complex stands. It is essential to use words that correctly convey the desired meaning to avoid misunderstandings in communication.