Defeaters are individuals or teams that overcome or prevent something from happening. Synonyms for this word include conquerors, winners, champions, vanquishers, and victors. Other options include achievers, contenders, overcomers, and supersede. Defeaters can also be described as triumphers, conquistadors, subduers, overpowerers, and subjugators. In some cases, the word can refer to people who prevent something from happening, in which case we can use synonyms such as preventers, obstructers, stoppers, hinderers, and blockers. Furthermore, words such as resisters, opponents, and enemies can be used to describe those who oppose the defeaters. Whatever the context and situation, there are plenty of words out there that can be used in place of "defeaters".