There are numerous synonyms for the term "spare bedroom". Some of the most commonly used ones include guest room, second bedroom, extra bedroom, additional room, bonus room, extra space, in-law suite, and multipurpose room. These terms are often interchanged depending on their usage and the context. An extra bedroom is typically utilized for accommodating overnight guests, while a bonus room could be used for various functions such as an office, home gym, or game room. An in-law suite, on the other hand, is specifically designed for long-term guests such as parents or in-laws. With so many diverse options, it's essential to choose a suitable synonym that fits the space's intended purpose.