jammy, adj.² — Green’s Dictionary of Slang

jammy adj.²

[lit. covered in jam]

(Aus.) unwashed.

1972		J. McNeill Old Familiar Juice (1973) 56: bulla: Who’s rotten socks are those? Hey? ’Oo leaves ’is jammy footwear lyin’ around the joint .
1984		Partridge DSUE (8th edn) 612/1: later C20.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Jammy. Unwashed.