keep down

verb

Please keep down your voice during the meeting.

意味（1）

(transitive) To repress.

China keeps down her dissidents very efficiently.

意味（2）

(transitive) To restrain or control (a sound).

We must keep the noise down, or the neighbours will complain.

意味（3）

(transitive) To cause not to increase or rise.

It is essential to keep the numbers down to avoid overcrowding.

意味（4）

(transitive) Not to vomit.

It is difficult to keep anything down when you have the flu.

意味（5）

(intransitive) To lie low. To stay concealed by not standing up

You had better keep down or they will see you.