The phrase "more sewed-up" means to be more confidently in control of a situation or outcome. Antonyms for this phrase would be words that convey the opposite meaning, such as "uncertain", "unpredictable", "chaotic", "disorganized", or "uncontrollable". A person or situation that is "less sewed-up" would be one that is less certain, less under control, and more likely to be influenced by external factors. The opposite of being "sewed-up" is to be "loose" or "unrestrained" - two more possible antonyms for this phrase that suggest a lack of control or order. In summary, antonyms for "more sewed-up" are words that suggest uncertainty, disorder, or lack of control.