The phrase "most sewed up" means something is well-organized, well-planned, and under control. Antonyms for this phrase would be words that describe something that is chaotic, disorganized, or unplanned. These words could include phrases like "in disarray," "out of control," "chaotic," "messy," or "unplanned." When something is not "most sewed up," it may be difficult to manage or deal with, causing stress and uncertainty. It is important to have a clear understanding of the opposite of "most sewed up" to fully comprehend and articulate the state of something that is not well-organized, well-planned, or under control.