吃夜草

chīyècǎo ㄔ ㄧㄝˋ ㄘㄠˇ

    • to pick up extra income on the side

Character by character

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
eat night fodder
Meaning
To pick up extra income on the side, from the saying that a horse not fed at night won't grow fat. Slightly knowing or mildly critical.

Sources