macaroni, n.³ — Green’s Dictionary of Slang

macaroni n.³

[joc. use of SE, but note later pony (and trap) n. (2)]

1. (Aus.) nonsense, meaningless talk .

1924		Lawrence & Skinner Boy in Bush 49: Yes. Jam, macaroni, cockadoodle. We’re plain people out here-aways, not mantle ornaments.
1941		Baker Popular Dict. Aus. Sl. 45: Macaroni, nonsense, foolishness.
1955		N. Pulliam I Travelled a Lonely Land (1957) 235/2: macaroni – silliness, nonsense.

2. negative emotion, e.g. worry.

1980

T. Lewis GBH 88: ‘Sammy. He’s in a constant state of macaroni at the moment’.