The word "most superincumbent" means something that is heavily and constantly pressing down on something else. Its antonyms, on the other hand, refer to something that is light, free, and unburdened. These include "weightless," "effortless," "buoyant," "unencumbered," "unobstructed," and "unburdened." These words describe the opposite of the weight and stress associated with superincumbent objects or situations. So, when the phrase "most superincumbent" is used to describe a heavy weight or pressure, its antonyms can help describe the feeling of freedom and lightness that comes with its absence.