The antonyms for "most well-dressed" can vary depending on individual preferences and context. However, some common antonyms for the term may include shabby, unkempt, slovenly, disheveled, and scruffy. These words imply a disregard for personal appearance and can convey a negative impression. Other antonyms may include plain, unadorned, unremarkable, and nondescript. While these words may not necessarily have a negative connotation, they suggest a lack of attention to fashion and trends. Ultimately, the opposite of "most well-dressed" depends on the situation and the standard of fashion being measured.