The opposite of the phrase "most zipped" can be described using a range of antonyms. These include "least zipped", "unfastened", "open", "loose", "slack", and "unsecured". If something is not zipped, it is considered unfastened, open or loose. On the other hand, if an object is securely fastened, it would be considered zipped, locked or tightly closed. Therefore, when something is not "most zipped", it could potentially have a range of antonyms depending on the context, such as "partially unfastened", "partially open", "somewhat loose", or "partially secured".