Green’s Dictionary of Slang

docker n.1

[Scot. docker, to work (hard)]

(Aus.) a large sum of money; thus go (in) a docker, to spend extravagantly.

Show quotations
[Aus]Age (Melbourne) 2 Nov. 6/2: The ‘sweeps’ were in strong force, even the ladies on the grand stand going in ‘a docker’ for this milder form of gambling.
[Aus]Teleg. (Brisbane) 23 Apr. 2/2: Going A Docker [...] a third of the men’s earnings is spent in drink, and their capacity for the consumption of schnapps is described as something remarkable.
[Aus]Baker Popular Dict. Aus. Sl.
[Aus]Baker Aus. Lang.

In phrases

go in a docker (v.) (also work a docker)

mid-19C+ Aus. to commit oneself wholeheartedly, to make a great effort.

Show quotations
Bell’s LIfe in Victoria (Melbourne) 6 Oct. 3/2: Jubus is a capital fencer and goes a good docker for so heavy a horse.
[Aus]Warwick Argus (Qld) 3 June 2/3: You [...] could go in ‘a docker’ at the dummying, but a man holding the dignified position of Warwick's representative must not think of such a thing.
[Aus]Hamilton Spectator (Vic.) 30 Apr. 3/3: Druid, is one we know can jump and go a docker, if the weight that he has got does not prove a stopper.
[Aus]Goulburn Eve. Penny Post (NSW) 11 June 2/3: The young ladies of Gunnedah go in a ‘docker’ for skating.
[Aus]Dead Bird (Sydney) 4 Jan. 4/1: For the steward worked a docker — he’d a mortgage on his head.
[Aus]Ovens & Murray Advertiser (Beechworth, Vic.) 24 Aug. 1/1: ‘Shearer’s Song’ [...] Now the last pen is folded, let’s go in a ‘docker’— / We soon shall be finished, my friends .
[Aus]Sydney Sportsman (Surry Hills, NSW) 18 May 2/4: Now fairly established their winter quarters, the management ot West’s Pictures are going In a docker In the way of supplying up-to-date goods.