Green’s Dictionary of Slang

dinky dirt n.

also dinkey dirt
[rhy. sl.; var. on dicky (dirt) n.]

(Aus./US) a shirt.

[US]A.J. Pollock Und. Speaks 31/2: Dinkey dirt, a shirt.
[US]Maurer & Baker ‘“Aus.” Rhyming Argot’ in AS XIX:3.
[Aus]Pete’s Aussie Sl. Home Page 🌐 dinky dirt: a shirt.