掛空擋

Simplified: 挂空挡

guàkōngdǎng ㄍㄨㄚˋ ㄎㄨㄥ ㄉㄤˇ

    • to go through the motions without achieving anything real

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
put the car in neutral
Meaning
To go through the motions in one's work without achieving anything real, like an engine running while the wheels do not turn. Mildly critical.

Sources