The antonyms for "boxed up" are varied and important to know in order to communicate clearly. The first antonym would be "free." When something is free, it has been released from confinement and is now able to move around and take up space. Another antonym for "boxed up" is "unrestricted," which means there are no limitations or barriers to movement or expression. The opposite of "boxed up" could also be "open," meaning that something is not enclosed or confined by walls or barriers. Finally, "unbounded" is an antonym for "boxed up." This word implies a sense of limitless or expansive freedom, without any kind of restrictions or limitations.