Green’s Dictionary of Slang

nummer n.

[ety. unknown]

a vagabond.

[UK]‘F.L.G’ Swell’s Night Guide K4: Nummer, A Low Vagabond.
[UK]Swell’s Night Guide 60: Nummy Ned goes on tout to the gardens, pipes a swell, stalls round him, fam’s him, touches the rumbo [...] pipes his ticker; them’ere precious gards is gallows quizbey fakements for us fammers. The Nummer spouts the tick and linker for quarteroo cooter – did the square with the kids.