Definition of put up or shut up in US English:

put up or shut up

phrase

informal
  • Justify oneself or remain silent.

    ‘they called for the alderman to either put up or shut up’
    • ‘He says the Select Committee should be given hard evidence, not just rumour, and employers should either put up or shut up.’
    • ‘He called on his opponents to put up or shut up.’
    • ‘‘People who want to make serious allegations against a Member of Parliament or, indeed, anybody else, have got to be prepared essentially to put up or shut up,’ Sir Philip said.’
    • ‘I want to conclude by challenging the Opposition today to put up or shut up.’
    • ‘In these circumstances he should put up or shut up.’
    • ‘Council chairman Coun Colin Lampard said: ‘We have got to the stage where they must either put up or shut up.’’
    • ‘‘The issue has been highlighted by me and others and it is now time for the government to put up or shut up,’ said Deputy Flynn.’
    • ‘The FDA was brand-new back then and told the companies to put up or shut up: prove your products are safe and effective or quit making them.’
    • ‘It's high time for all you governments to put up or shut up.’
    • ‘The two brothers at the centre of Australia's most infamous gold swindle have today told one of Western Australia's most senior policemen to put up or shut up.’