a nod's as good as a wink

said to mean that it is not necessary to explain something further, because you understand what someone has already told you indirectly

没有必要进一步解释一些事情，因为你理解了别人已经间接告诉你的事情

不用言明，心照不宣

这个短语的早期形式是a nod is as good as a wink to a blind horse。由于blind这个词的存在，有人说，其较长形式的原始含义是相反的，即无论一个人给出什么样的暗示，无论是点头还是眨眼，有些人都无法理解。这部分在19世纪被从这个短语中删除，这也改变了这个短语的意思。

例句：

No need to tell me what you were up to last night — a nod's as good as a wink.

没必要告诉我你昨晚在忙什么，懂的都懂。