Green’s Dictionary of Slang

anything that is bad.

1850		H. Mayhew in Advocate 18 Dec. 10/1: Business topics are discussed in a most peculiar style. One man takes the pipe from his mouth and says, ‘Bill made a doogheno hit this morning.’ ‘Jem,’ says another, a man just entering, ‘you’ll stand a top o’ reeb ?’ ‘Oh,’ answers Jem, ‘I’ve had trosseno tol, and have been doing dab’.
1856		H. Mayhew Great World of London I 5: I’ve had a reg’lar troseno (bad sort) to-day. I’ve been doing b----y dab (bad) with my tol (lot, or stock).
1859, 1860		Hotten Dict. of Modern Sl. etc.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 18/1: A coster declared that he was ‘a trosseno, and no mistake.’.
1873		Sl. Dict. 356: Trosseno literally, ‘one sort,’ but professional slangists use it to imply anything that is bad. tross among costermongers, means anything bad.
1882		Sydney Sl. Dict. (2 edn) 11: Trosseno - Anything bad (though lit. ‘one sort’).