The phrase "work of imagination" refers to something that has been created through the use of one's creative mind. There are many different synonyms for this phrase that can be used in various contexts. These include terms such as "creative output," "imagination product," "imaginative endeavor," "creative venture," or "artistic creation." Other possible synonyms include "fantasy work," "imaginative piece," "creative production," and "inventive creation." Each of these terms carries a slightly different connotation and may work better in certain situations than in others. Regardless of the specific synonym used, the overall meaning remains the same - something that has been created through imagination.