A guest room is a space designated to be used by visitors, which may include a bed and other basic amenities. A synonym for this phrase could be a spare room, which suggests that it is an additional room that can be used by guests or for other purposes. Another viable option would be a visitor's room, which is similar in nature to a guest room. Other possibilities include a lodging room, a hospitality room, or a guest suite. Ultimately, the term used can depend on the context and purpose of the space. Regardless of the label, the goal is to create an inviting and comfortable space for guests.