The antonyms for "most regularized" include "irregular," "unregulated," "unsystematic," and "inconsistent." An irregular system is one that lacks consistency or uniformity, making it difficult to predict and often leading to unexpected results. Unregulated refers to a system that operates without any established rules or guidelines, which can result in chaos and confusion. Unsystematic, similarly, refers to a lack of organization or structure in a system that operates without coherence or consistency. Finally, inconsistent suggests that a system is marked by variability or change, making it difficult to rely on or predict. Taken together, these antonyms describe systems that lack the stability and predictability associated with a regularized system.