Antonyms for the phrase "most loose fitting" could vary depending on the context. However, some common antonyms include "tight-fitting," "form-fitting," "snug," "fitted," "slim-fit," or "body-hugging." These words indicate clothing items that are designed to fit closely to the body, providing a sleek and flattering appearance. While loose-fitting clothes may be comfortable and casual, tight-fitting clothes are typically more stylish and appropriate for formal occasions. Remember that the choice of attire depends on personal style and preference, but antonyms for "most loose fitting" offer a good starting point for choosing outfits that fit the occasion.