The word "prevails upon" means to convince or persuade someone to do something. The antonyms for this phrase could be "dissuade," "discourage," "deter," or "restrain." If you are trying to prevent someone from doing something, you might use these words in conversation. For example, if someone wants to take a dangerous shortcut, you might try to dissuade them by pointing out the risks. Similarly, if someone is considering making a poor financial decision, you might try to restrain them by reminding them of their long-term goals. The antonyms for "prevails upon" highlight the importance of weighing consequences before making a decision.