The word "deep-worn" is often used to describe something that has been worn down to a significant degree. However, there are several synonyms that can be used to describe this type of wear. One such synonym is "weathered," which implies that the item has been exposed to the elements over a long period of time. Another synonym is "exhausted," which suggests that the item has been used so much that it has become worn out. "Worn out" is another alternative, indicating that the object has reached the end of its useful life. Lastly, "well-used" connotes the idea that the item has been used frequently but is still functional.