The word "most ceiled" can be rephrased using a variety of synonyms, depending on the context. For instance, "most covered" or "most concealed" are some synonyms that one can use when referring to something that is completely enclosed or hidden from view. "Most adorned" can be an appropriate synonym when one is discussing a space that's been decorated or embellished heavily with ornamental features such as moldings, patterns or sculptures. "Most roofed" can also be a synonym when referring to a building or structure that has a roof, while "most sheltered" can be an appropriate alternative when discussing animals or humans who are well-protected from harsh weather conditions.