Definition of flash jack in English:

flash jack

noun

Australian
informal
  • A man who dresses or behaves ostentatiously.

    ‘we don't like flash jacks hanging round our girls’
    • ‘I let out that I am pretty well acquainted with the young man—the 'flash Jack' they have been discussing.’
    • ‘Their hearts and applause went out to the manager, to the flash-jacks of bits of Broadway successes of the past.’
    • ‘He's a Flash Jack, plays polo, wants his own plane next, I'm told.’
    • ‘Now the banks have had to go back to steady eddies after the flash jacks have had their wicked way.’
    • ‘You are not so easily conned by English-speaking flash jacks.’