Green’s Dictionary of Slang

(Aus.) a city-dwelling business man who poses as a farmer, and may own a rural property (which is never visited).

1913		Truth (Perth) 14 June 4/4: Terrace Cockies and Back Block Hardship [...] The St. George’s Terrace ‘cocky’ is not nearly so much in evidence since the tales or hardships in the backblocks have filtered through to Perth.
1940		Western Mail (Perth) 15 Aug. 30/5: [A]lthough I suppose I must now be regarded as a ‘St. George's-terrace cockie,’ it takes more than five years in the city to wipe out the memories of most of a lifetime in the country.
1993		Aus. Word Map 🌐 St Georges Terrace cocky. one who owns a country property, often for tax loss purposes, but who lives and works in Perth. Compare Pitt Street farmer, Queen Street bushie, Collins Street cocky.