I'm a layman of aviation.

我是航空业的门外汉。

He is a layman of this religion.

他是这个宗教的在俗教会教徒。

As a layman, I had no idea what they were talking about.

作为一个外行，我一点都听不懂他们在讲什么。

That's the difference between a professional and a layman.

那就是专业人员跟外行人的不同点了

The subject matter was so technical as to be beyond the ken of the average layman.

该主题专业性太强，一般的外行人很难理解。

The mere mention of the words "heart failure" can conjure up, to the layman, the prospect of imminent death.

一提到“心力衰竭”几个字，外行人就会想到立即死亡。

Where the law is concerned, I am only a layman.

谈到法律，我不过是门外汉。

I'm a layman. What I'm going to say may expose myself to ridicule, yet I still want to say a few words.

我是个外行，我说的话可能贻笑大方，可我还是要说几句。

He is a layman in economics.

他对经济学一窍不通。