Green’s Dictionary of Slang

(Aus./UK juv.) saliva or phlegm, in the context of spitting; also nasal mucus.

1993		Aus. Word Map 🌐 goozy. ‘Secretions from nose or lungs as opposed to saliva. Snot or phlegm. Perth and central WA: “You've got a goozy hanging out your nose”.’ ‘A piece of phlegm in the back of the throat that is spat out: I had a goozie in my throat’.
2001		OnLine Dict. of Playground Sl. 🌐 gozzy n. spit.