The antonyms for the word "co-operators" are "opponents," "dissidents," "nonconformists," "antagonists," "detractors," and "enemies." These individuals or groups are against the idea of cooperation and collaboration, leading to conflicts and disagreements. Opponents are those who are against a particular idea or project, while dissidents usually oppose an established system or government. Nonconformists are people who resist conformity to conventional norms and values. Antagonists are those who oppose or compete with others, and detractors are individuals who actively criticize and seek to undermine the success of others. Enemies, on the other hand, have a deep-rooted hostility towards others and seek to harm them in any way possible.