The phrase "ship out" has several antonyms, including "retrieve," "keep," and "retain." While "ship out" implies sending something away, "retrieve" suggests bringing it back. If you have shipped out a package, you might later retrieve it if it was returned or if you changed your mind. Similarly, if you are asked to ship something out but decide to keep it, you are retaining it. The opposite of shipping out can also be expressed as simply keeping or storing something rather than getting rid of it. Overall, the antonyms for ship out highlight the idea of holding onto something rather than letting it go.