Sentence:  In order better to appreciate the use of argot among thieves, a visit to a few public bars of the third-class public houses of Kennington or in the immediate vicinity of the Elephant and Castle would prove of great value, as hoisters, <WSD>whizzers</WSD>, tea-leaves, con-heads, broadsmen and brass nobs ... 
Meaning of the word marked with <WSD> tags:  A pickpocket.