Undressed, as the word suggests, refers to something that is not properly dressed or is in a state of undress. The antonyms of this word would be those that are associated with being dressed and presentable. Some of the antonyms for undressed are clothed, dressed, adorned, decorated, embellished, groomed, preened, and spruced up. These words indicate a state of being properly dressed and made presentable. Using antonyms of undressed in a sentence, such as "She always arrives at work immaculately dressed," or "He looked suave and sophisticated in his well-adorned attire," can help to better express the desired sense of being dressed and presentable.