Definition of sleep on it in US English:

sleep on it

phrase

informal
  • Delay making a decision on something until the following day so as to have more time to consider it.

    • ‘I had some misgivings, and he had some misgivings, so I suggested he sleep on it overnight before rushing into a decision.’
    • ‘I don't regret any of what I said, because it was how I was feeling at the time, but I do regret that I didn't sleep on it and give some thought to the tone and content.’
    • ‘Glendon said: ‘Lee changed his mind after sleeping on it and stated he was happy at Rammy.’’
    • ‘After sleeping on it, I decided I probably could have waited longer for the levity.’
    • ‘I slept on it, and I still think it is a good point.’
    • ‘‘She said she wanted to sleep on it,’ the care worker said.’
    • ‘He said he's sleeping on it and is going to make a decision tomorrow.’
    • ‘Having slept on it, I think it's probably fair to conclude that the media reported Clark's statements accurately.’
    • ‘Perhaps if he slept on it, he might find a solution.’
    • ‘If only those around him had persuaded Mr Howard to sleep on it; to take the whole weekend off.’