There are several synonyms that can be used in place of the term "adjoining room". Some examples include "connected room", "adjacent room", "neighboring room", "contiguous room", and "suite." All of these terms refer to a room that is situated next to or near another room, often with a connecting door or easy access. Whether you're looking to book a hotel room or describe your home's layout, these synonyms can help add variety to your language and make your writing more interesting and engaging.