He went underground to avoid arrest.

他隐藏起来以防被捕。

《牛津词典》

After the violent clashes of 1981 they either went underground or left the country.

1981年的暴力冲突之后，他们要么转入地下了，要么离开了这个国家。

《柯林斯英汉双解大词典》

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

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