外行的英文：
layman
unprofessional

参考例句：

Orthopaedics is outside his territory.
他对整形外科是个外行。

Not professional;unskillful.
外行的;技术不佳的

An amateur shouldn't play roulette for high stakes.
外行不该下大赌注赌轮盘赌。

Gordon, I’m not an amateur! I love that baby and I am scientific.
戈登，我不是外行！我爱小宝贝，我懂得科学育婴。

A layman or a laywoman.
男外行，女外行

Of or relating to the laity;secular.
外行的，世俗的外行的或与之有关的;世俗的

He's strange to the work.
他对这工作很外行.

He was but poorly acquainted with such matters
他对这类事情是外行。

I am strange at tennis and golf.
我对网球和高尔夫球是外行。

I am a layman in the field of economics.
在经济问题上，我是个外行

layman是什么意思：
n. 门外汉，外行人，普通教徒

Quercus, or, to the uninformed layman, the oak..
栎属乔木,亦即外行人所谓的橡树....

He is only a layman authorized to read sermons.
他就是一个被授权布道的普通教徒。

The layman is generally more concerned with their possible unethical uses
外行人通常担心它们可能产生非道德的用途。

When it comes to meteorology, I'm just a layman.
谈到气象学，我只是个门外汉。

In general, both books succeed in being as engaging to the layman as to the practising or studying doctor.
总体来说，两本书不论对于门外汉，还是实习或是学习中的医生，都很有吸引力。

unprofessional是什么意思：
adj. 违反职业道德标准的，不专业的

The reporter was accused of unprofessional conduct.
那位记者被控有违反职业道德的行为。

It's unprofessional to go round criticizing your colleagues.
四处活动批评同事是不符合职业道德的。

The board considers your behaviour highly unprofessional.
董事会认为你的行为严重违反职业道德.