In situ is a Latin term that means "in place" or "on-site." As such, antonyms of in situ include "out of place," "out of position," "moved," or "displaced." An object or element that has been removed from its original location or context would not be considered in situ. Alternatively, you could use the synonyms "transplanted," "relocated," or "repositioned" to describe things that have been moved from their original location. While the opposite of in situ can depend on the context in which it is used, it generally refers to something that is not currently in its original position or location.