The word "spikier" implies something sharp, pointed, or prickly. Its antonyms, on the other hand, connote smoothness, softness, and curvature. Words such as smooth, rounded, oval, sleek, and polished are some examples of these antonyms. Smooth signifies a lack of roughness or bumps, while rounded implies gentle curves rather than sharp angles. On the other hand, sleek means smoothness or avoiding roughness, and polished refers to something that is smooth and shiny. By using these antonyms for "spikier", one can convey a different meaning from the original word, highlighting a different set of attributes that can contrast with those of "spikier".