keep it on the down-low

keep (something) on the down low

To keep something in a state of secrecy or minimal public knowledge; to not share something with anyone else. Keep this on the down-low, but Janet is planning to break up with Kevin next week.
See also: down, keep, low, on

keep it on the ˈdown-low

(American English, slang) keep something secret; not tell other people about something: Her parents wouldn’t approve of our relationship so we keep it on the down-low.
See also: keep, on