flat stick adjective 1adverb 1noun 1forms 3 adjective1 •(Australia, New-Zealand) Extremely busy or fast-paced."Only thing is, I'm flat stick. Can't get onto it until the end of the month. You wanna courtesy car?" — 2010 adverb1 •(Australia, New-Zealand) As quickly as possible; at top speed.He then drives us flat stick into the setting sun to home. — 2012 noun1 •A golf club intended for putting; a putter. formsflat sticks · more flat stick · most flat stick