The word "amyloidal" refers to substances that resemble or contain starch. Its antonyms are words describing substances that are non-starchy or do not contain any starch. Some examples of such antonyms for amyloidal could be watery, oily, fatty, or proteinaceous. These words describe substances that are entirely different in composition, texture, and appearance compared to amyloidal substances. Other antonyms for amyloidal could include smooth, soft, or liquid, as these words describe substances that lack the granular, rigid appearance of amyloid. Thus, amyloidal is a specific term that refers to a unique property of substances, and its antonyms highlight the diversity of substances in the natural world.