Backbreaking works refer to tasks or activities that involve heavy physical labor and can cause strain or injury to one's back. Fortunately, there are several synonyms for this term that you can use in your writing. Some of the most common include grueling, exhausting, arduous, strenuous, demanding, tiring, and laborious works. These synonyms can be useful for adding variety and depth to your writing, as well as for expressing the difficulty and intensity of physical labor. Whether you're describing the challenges of farming, construction, or manufacturing, using synonyms for backbreaking works can help to convey the sense of effort and dedication required for these tasks.