noun · A person whose remarkable talents or mastery are not widely known or remain concealed.

这位不起眼的程序员其实是公司的扫地僧，解决了很多核心难题。

The nameless monk who maintains the library of Shaolin in Jin Yong's novel "Demigods and Semidevils".

扫地僧是《天龙八部》中武功最高强的人物之一。