根子硬

gēnziyìng ㄍㄣ ˙ㄗ ㄧㄥˋ

    • to have powerful backers and a secure position
    • to be hard to touch

Character by character

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
the root is hard
Meaning
Says that someone has powerful backers with a secure position, so they are hard to touch.

Sources