Nodulous is an adjective used to describe something that has small nodules or bumps. Antonyms for this word include smooth, flat, even, level, and unblemished. Smooth describes a surface that is completely even and without any bumps or ridges. Flat means something that is level and without any bumps, dips or curvature. Even describes a surface that has an equal level throughout. Level refers to a surface that is flat, horizontal, and equal in height at all points. Unblemished describes something that is without any marks, spots, or damage. These antonyms are used to describe surfaces and objects that are opposite in texture and appearance to something nodulous.