He went underground to avoid arrest.

他隐藏起来以防被捕。

《牛津词典》

He went underground when he heard the police were after him.

他听到警察要抓他就躲了起来。

youdao

Karadzic went underground in 1997 and had been on the run ever since.

1997年，卡拉季奇藏匿起来，逃亡至今。

youdao

Harriet went from house to house that way on the Underground Railroad.

VOA: special.2011.02.13

Mudrian says that, freed from the pressure of the mainstream, metal went underground.

NPR: Kicking and Screaming, Metal Back in Music Spotlight

Most of the contributions under scrutiny were traced to Huang, who went underground in the last weeks of the campaign and has only briefly resurfaced.

CNN: Campaign Finance: The Show Begins

But instead of disappearing, the trade went underground and radically changed.

FORBES: Inside Dope