昙花一现用英语说就是a flash in the pan。

That singer was only a flash in the pan. He disappeared into the air after having made one or two records.

那个歌星也只是昙花一现，出了几张唱片就销声匿迹了。

flash

①闪光；闪耀 a flash of lightning一道闪电

②（情感的）突发；（想法的）突现

The idea came to her in a flash of inspiration/genius.灵光一闪，她便有了这个主意。

③闪光灯；闪光操纵装置

Where's the flash for the camera?照相机的闪光灯在哪儿？

It's dark in here, I'll have to use the flash.这里相当暗，我得用闪光灯。

④飞快的一瞥

She leaned over and I caught a flash of pink underwear.

她屈身过来，我一眼瞥见了粉红色的内衣。