A qualifier is someone who is successful in one part of in a competition and goes on to the next stage.
双语例句
例：
Kenya's Robert Kibe was the fastest qualifier for the 800 metres final.
肯尼亚的罗伯特·凯布是800米决赛入围者中速度最快的选手。
2.?[C 可数名词] 预选赛
A qualifier is an early round or match in some competitions. The players or teams who are successful are able to continue to the next round or to the main competition.