The phrase "down-at-the-heel" typically means shabby, worn-out, or in a state of disrepair. Its antonym, therefore, would be something that is stylish, sophisticated, and well-maintained. A few possible antonyms could include polished, elegant, refined, sleek, smart, pristine, or immaculate. These words suggest the opposite of something that is dilapidated or unkempt, evoking a sense of cleanliness, orderliness, and good taste. To use an antonym for "down-at-the-heel" might describe a chic, newly renovated apartment or a freshly tailored suit. It presents an opportunity to celebrate the beauty and elegance of things that are well-maintained, rather than focusing on their fragile or decrepit state.