The antonym for "unpacking" is, of course, "packing". Packing is the process of putting items into containers or bags to store, move or ship them elsewhere. Unlike unpacking, which is done when you arrive at a destination, packing is done when you are leaving one place and going to another. Other antonyms for the word "unpacking" could include leaving, departing, or vacating, which imply that a space is being cleared and left empty. These terms denote the opposite action to unpacking, as they refer to removing or taking things away rather than bringing them in and organizing them.