yáo​qián​shù

cash cow

摇钱树 (搖錢樹) yáo​qián​shù
cash cow noun
a person, business, or thing that is a source of easy and reliable profit

This film franchise has become a cash cow for the studio.

money tree verb
a legendary tree in folklore that sheds coins when shaken

Legend says that if you shake this money tree, an endless supply of gold coins will fall from it.

Frequency

Movie subtitles
1.22 per million appears in 1% of films
Written text
0.957 per million

Sources

Definitions
CC-CEDICT