Oh, in that case, he doesn't have a leg to stand on!

哦，在那种情况下，司机说的话就站不住脚了。

Let it go. The kids walked for 3 miles to get here. We don't have a leg to stand on.

算了吧。孩子们走了3英里路跑到这里。我们的腿都会受不了。

Not having a leg to stand on means a person does not have any evidence to support his or her argument.

站不住脚的意思是，一个人没有任何证据来支撑他自己的论点。

The other side doesn't have a leg to stand on.

对方的说法站不住脚。

But trust me, we don't have a leg to stand on.

但相信我 我们也没有站得住脚的理由反对。

If you didn’t sign a contract, you won’t have a leg to stand on.

【leg】如果你没签合同的话，你就没有东西可以依据了。