Green’s Dictionary of Slang

dab tros n.

also dob tros
[backsl.; dab adj.2 ]

a bad sort, an unpleasant person.

[UK]Hotten Dict. of Modern Sl. etc.
[UK]Sl. Dict.
[UK] press cutting in J. Ware Passing Eng. of the Victorian Era 115/1: If a chap happens to be a dab tros he gets on better than a doogheno who keeps himself quiet and never lets anybody Tommy Tripe know how clever he is.
[Aus]G. Seal Lingo 41: Thus the police became esclops, delo nammow is an old woman and a bad sort became a dob tros.