keep somebody/something ↔ down phrasal verb ( see also ↑ keep )
1 . to prevent the size, cost, or quantity of something from increasing or being too great:
We need to keep costs down.
2 . to succeed in keeping food in your stomach, instead of bringing it up again out of your mouth, when you are ill:
I could hardly keep anything down for about three days.
3 . used to ask someone to make less noise:
Keep your voice down – she’ll hear you!
Can you keep it down – I’m trying to work.
4 . to prevent a group of people from becoming as successful and powerful as the other people in a society:
Plantation owners kept slaves down by refusing them an education.