Definition of flat stick (or tack) in English:

flat stick (or tack)

phrase

Australian, NZ
informal
  • As fast or as hard as possible.

    ‘he went flat stick from the start no matter how far the race’
    • ‘Her oar must have caught a little wave and rolled the boat straight over because they were going flat tack.’
    • ‘I don't know why the rest of my colleagues didn't say something to me because I was talking flat tack.’
    • ‘Staff had been "flat tack" all day and had been called to about five electrical fires caused by fallen power lines.’
    • ‘The youngster had been flat stick, working shifts at a radio station, working in his uncle's shop, and even cleaning cars.’
    • ‘The rumour mill is going flat stick about him not lasting the distance this election.’