根子正

gēnzizhèng ㄍㄣ ˙ㄗ ㄓㄥˋ

    • to have a clean background and sound political thinking

Character by character

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
the root is straight
Meaning
Says that someone has a clean background and sound political thinking. It is approving, in an official-political sense.

Sources