Antonyms for the word "bottom-most" could be "topmost," "uppermost," "highest," or "top." These words describe positions that are located above or upward. For instance, when referring to a pile of books or a stack of boxes, the topmost one would be the one that is placed on the highest point of the pile. Similarly, a top or uppermost layer of soil or rock indicates the layer that is situated at the topmost point and closest to the surface. These antonyms are useful in differentiating between the highest and the lowest points of any object or surface.