Green’s Dictionary of Slang

(N.Z.) an otherwise nameless object, often a gadget.

1998

DNZE 357/2: hoodicky. Also hoodackie and other spoken variants. A mainly young people’s name for a thingamebob. (The following variants have been noted from c1940 to c1951: doodacky, doohickey, hoodle-lacky, hoojacky, hoojah, hoojit, howdzacky.).