umpire

Compared meaning: to judge a sports match or dispute (verb).

比较义项：担任裁判，裁定比赛或争端（动词）。

• referee

  Used mainly for sports with a single official who can also actively intervene physically, such as football, boxing or rugby; the referee often blows a whistle and can stop play directly.

  主要用于由一名裁判执法、且该裁判有时需要亲自介入比赛的运动，如足球、拳击或橄榄球；裁判常吹哨并可直接叫停比赛。

  He has refereed top-flight football matches for over a decade.

  他已经执法顶级足球联赛的比赛超过十年了。

• umpire 本词

  Used mainly for sports where officials watch from a fixed position and make calls without physically intervening, such as cricket, tennis or baseball.

  主要用于裁判从固定位置观察并做出判罚、而不亲自介入比赛的运动，如板球、网球或棒球。

  She umpired the tennis final and overruled a controversial line call.

  她担任那场网球决赛的裁判，并推翻了一个有争议的界内判罚。

Both mean to judge a match, but for different sports. Referee fits sports where officials can step in physically, like football, boxing, or rugby. Umpire fits sports where officials watch from a fixed spot, like cricket, tennis, or baseball. Its noun sense isn't compared.

这两个词都指在比赛中执法、维持规则，但适用的运动项目不同，不能随意互换；这里不比较 referee 作名词时指“裁判员”这一身份用法，只比较其动词用法。