The word "un-sightly" means unpleasant, unattractive or ugly in appearance. There are many antonyms for "un-sightly," which include beautiful, stunning, pretty, attractive, charming, and delightful. These words describe something visually appealing and pleasing to the eyes. The antonyms of "un-sightly" can also be used to describe a person's appearance, nature, behavior, attitude, and surroundings. By using these antonyms, we can create a positive and optimistic impact on our surroundings, thoughts, and emotions. So, whenever you want to express the opposite of unattractive, you can use any of these antonyms and make your writing more vivid and inspiring.