The word "most unbeautiful" denotes something that is extremely unattractive, unpleasant or ugly. However, there are several antonyms to this word that can be used to describe something that is beautiful, charming or pleasing. Some of the most common antonyms for the word "most unbeautiful" include words such as attractive, stunning, gorgeous, lovely, stunning, pleasing, and captivating. These words indicate a sense of awe, admiration, or appreciation for something that is visually appealing or attractive. So, whenever you encounter something that is the opposite of "most unbeautiful," you can use these words to describe it in a more positive light.