Definition of down-low in English:

down-low

noun

in phrase on the down-low
  • 1US informal On the quiet; in secret.

    ‘he kept his status as a Hell's Angel on the down-low’
    • ‘Occasionally, he punctuates the flow with the more upbeat rhythms of tracks like ‘Inside’ or ‘Brotha Man,’ but mainly he keeps everything on the down-low, using an interesting mix of pop-rock and R&B.’
    • ‘The note-passing had to be kept on the down-low as not to alert the plentiful U.S. Border Patrol, who are ordered every February 14 to dissuade the passing of notes and gifts due to suspicions of drug trafficking.’
    • ‘A piece of news had reached the apex of its life, and I felt somewhat responsible for seeing it through from a tip on the down-low, to an op-ed piece above the fold.’
    • ‘There's still the slight complication of keeping it on the down-low so that people who didn't get invited don't get their feelings hurt, but I think it will all work out.’
    • ‘But details on that are staying on the down-low until Friday.’
    1. 1.1(of a man) concealing his homosexual tendencies.
      • ‘Or perhaps they are, secretly, on the down-low.’
      • ‘He describes "down low detectives" as women who spy on their husbands to ascertain if they are on the down low.’
      • ‘Shaming men about their sexual orientation only encourages them to be on the down-low.’
      • ‘Many men who have sex with men chose to live their lives in the closet or on the down-low.’
      • ‘Because the down low is defined by secrecy, almost nothing is known about the number of men who are on the down low.’

Origin

1990s originally in African-American usage.