top dog按照字面意思理解，它的意思是“顶尖犬”，但是其真正的意思可完全不是这样的，指的就是：一个人、一个群体或者一个国家在某个方面或者比赛中处于领先或者优胜的地位，也就是“优胜者，佼佼者或者权威”。

【例句】
I don't want to be the top dog at our company. I just do my job as well as I can.
我不想成为我们公司的佼佼者，我只是尽我所能做好我的工作。

And the idea that one nation was top dog and had in some way won the games has always been considered anathema.
有关某个国家是优胜者、以某种方式赢得奥运会的说法，一直被视为令人讨厌。