zhuāng​shǎ

play dumb

装傻 (裝傻) zhuāng​shǎ
play dumb verb
to feign ignorance or lack of intelligence, often to avoid responsibility or an awkward situation

Don't play dumb with me; I know you did it.

feign innocence verb
to pretend to be naive or lacking in worldly experience

She is best at playing dumb to make everyone think she is innocent.

Frequency

Movie subtitles
3.76 per million appears in 2% of films
Written text
2.73 per million

Sources

Definitions
CC-CEDICT