The word "un-intelligible" is used to describe something that is difficult or impossible to understand. Its antonyms are words that describe the opposite of this meaning. Some antonyms for "un-intelligible" include clear, coherent, articulate, lucid, and understandable. These words imply that the message or idea being conveyed is easily comprehensible and can be grasped without much effort. They suggest that the speaker or writer has succeeded in conveying their message in a way that is easily understood by their audience. Using these antonyms can help to make communication clearer and more effective, resulting in better understanding and less confusion.