Antonyms for the word "most grassroots" could be "least influential," "elite," "establishment," or "top-down." These words portray the opposite aspect of grassroots, which is often associated with a bottom-up, people-driven approach. While grassroots movements are characterized by their wide and diverse support base, the antonyms highlighted above epitomize a centralized and exclusive form of power, where decisions are made by a select few. These antonyms represent a different type of political, social, and economic system, one diametrically opposed to the values and ethos of grassroots activism.