zì​zuò​cōng​míng

presumptuous

自作聪明 (自作聰明) zì​zuò​cōng​míng
presumptuous idiom
to think oneself clever; to act smart

He always tries to be clever, but ends up making things worse.

Frequency

Movie subtitles
2.30 per million appears in 1% of films
Written text
0.807 per million

Sources

Definitions
CC-CEDICT