zhāng​zuǐ

to open one's mouth

张嘴 張嘴 zhāng//zuǐ
to open one's mouth verb + noun
to open the mouth, often as a precursor to speaking or singing; to gape

I thought he was criticizing you for chewing with your mouth open or something like that.

to ask for a favor
to open one's mouth to ask for a loan, help, or a favor

Frequency

Movie subtitles
1.31 per million appears in 1% of films
Written text
2.67 per million

Sources