The spelling of the word "most sewnup" may seem a bit confusing, but it actually makes sense when broken down phonetically. The word is pronounced /moʊst səʊn ʌp/ and is a phrase meaning that something is almost guaranteed or certain. The spelling of "sewnup" may look odd, but it is simply a combination of the words "sewn" and "up" and is used to convey a sense of completion or finality. Despite its unusual appearance, the spelling of "most sewnup" is a valid representation of the English language.
The phrase "most sewnup" does not have a specific etymology as it is a combination of the words "most" and "sewn up". "Most" is a superlative form of "many" or "much" and is used to indicate the highest degree or extent of something. "Sewn up" is a phrasal verb that means to complete or finalize something, usually successfully or thoroughly. The combination "most sewn up" indicates that something is very well completed, secured, or controlled.