The phrase "most raftered" refers to a structure or building that has the most rafters, or beams that support the roof. Some synonyms for this phrase include "most beamed," "most trussed," or "most supported." These words convey the same meaning as "most raftered" and can be used interchangeably to describe a building or structure that has a strong and sturdy roof. Other synonyms include "most fortified" or "most reinforced," which suggest strength and durability. Ultimately, whichever synonym you choose to use will depend on the context and tone of your writing, but each one conveys the same idea of a structurally sound roof and building.