The antonyms for the word "agrees upon" are discord, dissent, disaccord, conflict, oppose, and differ. Discord refers to a lack of harmony or agreement among two or more parties. Dissent is a disagreement or difference of opinion, particularly in a formal setting such as a meeting or debate. Disaccord denotes a lack of unity or harmony, particularly in a musical context. Conflict is a state of opposition or disagreement between two forces, ideas, or individuals. Oppose means to disagree strongly or to act in opposition to something. Differ refers to a disagreement in opinion or belief. By utilizing these antonyms, the speaker or writer can express disagreement or opposition to a previously agreed-upon idea, concept, or decision.