Maintopmast is a nautical term typically used to describe a specific part of a ship. However, there are a few synonyms that can be used as alternative terms for maintopmast. Some of the most commonly used synonyms for maintopmast include topgallant mast, topmast, or just plain mast. A topgallant mast usually refers to the uppermost part of a sailboat's mast, while a topmast refers to any part of a ship's mast above the lower mast. Using a synonym for maintopmast in nautical terminology can add some variety and color to your language and can help you communicate more effectively with other sailors and boating enthusiasts.