"Hollows out" is a term that is commonly used to describe the process of creating a cavity or empty space within an object. If you are looking for synonyms for this phrase, there are several different options that you can consider. For example, you might use terms like excavates, carves out, hollows, or scoops out. Alternatively, you could use words like bored, drilled, or dug to describe the process of creating a hollow space. Ultimately, the best synonym to use will depend on the specific context in which you are writing, as well as the level of precision that you wish to achieve in your language.