Quack  A Medical Officer.

General Australian. From 1919 (AND). Attested in numerous sources.

‘Quack’ from the 17th century referred to ‘a medical charlatan’. The neutral sense, as used here, is Australian.

Quarter-bloke  Quarter-master.

General World War I. From 1919 (OED). Attested in numerous sources.

Quick Dick

World War I. Attested in Cutlack, F&G, and Partridge.

This was a nickname for a high-velocity gun (Cutlack).

*Quiff  An idiosyncracy. ‘Regimental Quiff’, a method of performing a drill movement.

General military. Attested in B&P, Digger Dialects, and F&G.

This is a specific adaptation of ‘quiff’ meaning ‘a clever trick or dodge’, from 1881 (OED). F&G provide the following explanation of its use in a military sense: ‘Any specially ingenious smart, tricky, or novel or improvised way of doing anything (Navy). In the Army used of any drill method peculiar to a battalion, and not usually done in others. Where the wording of the Drill Book is vague, units often read different meanings into the phraseology and invent their own “Quiffs”’.