Green’s Dictionary of Slang

lumberer n.2

[lumber v.1 ]

1. a pawnbroker.

[US]Matsell Vocabulum.
[UK]Farmer & Henley Sl. and Its Analogues.

2. a swindling tipster.

[UK]Sporting Gaz. (London) 30 Oct. 1108/3: [T]hat still more dangerous specimen of humanity known by the slang term of ‘lumberer,’ who invariably prey upon the young and unsuspecting.
[Aus]Bulletin (Sydney) 18 July 18/3: The temperance principles of the bully are as dear to him as the teetotal orator […]. A certain notorious English ‘welsher’ and ‘lumberer,’ known in police circles as Bill the Butcher, is a non-smoker and a sort of temperance apostle among his ruffianly friends.
[UK]A. Binstead Gal’s Gossip 146: A bold, fearless narrative in song of the glories achieved by a squad of Her Majesty’s favourite regiment of Lumberers.
[Aus]Sydney Sportsman (Surry Hills, NSW) 9 Mar. 3/5: One of the lumberers undertook to act as his guide, philosopher, and friend and started to lumber him on to a double.
[UK]S. Jackson An Indiscreet Guide to Soho 121: Petty ‘lumberers’ (con. men who do rapid kerbside deals like taking money for liquor from drunken victims and then disappearing.
[UK]P. Hoskins No Hiding Place! 191/1: Lumberers. Kerbside confidence tricksters.
[Aus]G. Seal Lingo 146: As well there were other varieties of cheat including a lumberer, a tipster who swindles.

3. any form of swindler.

[Aus]Herald (Melbourne) 6 Aug. 2/7: [of card-sharps] They Say [...] A party of ‘lumberers’ [...] taking on a well-known Boniface who knew his way around.
[UK]Sporting Gaz. (London) 8 Sept. 1097/2: Probably several of my readers have also been robbed, perhaps will even be done this very year by a class known in slang parlance as ‘lumberers,’ men who live well, dress smart, and especially frequent the Gaiety and Criterion restaurants.
[UK]‘Doss Chiderdoss’ in Sporting Times 6 Mar. 1/4: Two Johnnies lose, / Two partners win; / Two lumb'rers take / Two piles of tin.
[UK] divorce court report July in Ware (1909) 171/2: Mr Gill felt instinctively that there was something wrong with this man’s appearance; and when this man came, in cross-examination, to give an account of himself, it accorded with the well known expression ‘lumberer’.
[UK]Binstead & Wells Pink ’Un and Pelican 126: ‘Pimples’, as the lumberer was called among his kind, was by no means a desirable security.
[UK]‘Doss Chiderdoss’ ‘Poetry in Prosaic Places’ Sporting Times 19 Feb. 3/2: The most transparent lumberer in town who on him works / The old ‘Confidence’ manoeuvre, scoops the pool.

4. a prostitute or pimp who specializes in robbing her/his clients.

[Aus]Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] LUMBERER: A brothel tout, a man who decoys men down lanes or alleys or into bilking houses for purposes of robbery.
[Aus]Baker Popular Dict. Aus. Sl.
[US]Trimble 5000 Adult Sex Words and Phrases.

5. (Aus.) a traffic police officer (c.f. walloper n.1 (8)).

[Aus]D. O’Grady A Bottle of Sandwiches 19: The lumberer got off his bike [...] faced our truck and surveyed the number plate.