口は

opening; mouth

→ 口
phrase Rare #23,854
opening; mouth 口 can mean an available position or opening, as in 仕事の口. In 口はよせ, it refers to speaking and the phrase means “stop talking” or “hold your tongue.”
JA: この会社にはまだ一つ採用の口はある。
EN: This company still has one opening.

口は閉じておけ目は開けておけ

Keep your mouth shut and your eyes open.

口は堅い

Can you keep a secret?

口は達者だな

You sure are good with words.

— ミッション・クレオパトラ (2002)

だが口はよせ

But hold your tongue.

— ウエスタン (1968)

口は乾いていました

My mouth was dry.

彼女は口は悪いですけど根は優しい人ですよ

She may have a sharp tongue, but deep down, she's a kind person.

口は災いの元

Loose lips cause trouble.