Futtock is a nautical term that refers to a curved timber used in shipbuilding. While it may not be a word commonly used outside of maritime contexts, there are several synonyms that can be used in its place. Some possible alternatives include rib, frame, bracket, or even simply a curved piece of wood. In many cases, the specific synonym used may depend on the context in which it is being used. Nonetheless, all of these options can serve as suitable substitutes for futtock when describing similar structural elements used in construction or other projects.