Antonyms are words that have opposite meanings. The word "centroidal" means relating to or resembling a centroid, which is the geometric center of a figure, such as a triangle or a circle. The antonyms for this word would be terms that suggest the opposite of centrality, such as decentralized, scattered, or diffuse. Other antonyms might include peripheral, marginal, or eccentric, which imply a position farther out from the center or outside the main focus or interest. In short, antonyms for "centroidal" connote a lack of centrality or focus, suggesting a broad or diffuse dispersal of elements.