Oneup means to surpass or gain an advantage over someone or something. Some synonyms for this word include outdo, outshine, outclass, outmatch, outrank, surpass, top, beat, exceed, and excel. These words all carry a similar meaning and can be used interchangeably with oneup to describe a situation where someone has gained an advantage over another. Whether it's in the classroom, on the sports field, or in the workplace, there are always people striving to be the best and outperform their peers. Using these synonyms can help to add variety and depth to your writing or conversation, while still conveying the same message.