Green’s Dictionary of Slang

(UK Und.) a thief who robs private rooms or houses; thus parlour-jumping, practising such a form of robbery.

1879		‘Autobiog. of a Thief’ in Macmillan’s Mag. (London) XL 500: This time I palled in with some older hands at the game, who used to take me parlour-jumping (robbing rooms) putting me in where the windows was open.
1887		‘Aus. Colloquialisms’ in All Year Round 30 July 67/1: A thief of the present day would talk of ‘parlour-jumping’ when he referred to taking things from a sitting-room.
1894		A. Morrison Tales of Mean Streets (1983) 151: An ocasional deviation into parlour-jumping.
1898		Daily Tel. 4 Aug. in Ware (1909) 193/1: A constable explained that the prisoner was known as a ‘parlour-jumper’. This, in ordinary language, meant that he went in for robbing rooms.
1925		N. Lucas Autobiog. of a Thief 105: No self-respecting crook will ‘parlor jump’ if there is any more attractive work on hand [...] ‘Parlor jumpers’ go round knocking at the doors of likely houses in the suburbs of London and other towns. If the door is answered, they ask for food, or money for some fictitious person, and try their luck elsewhere. Should they find a house empty of its usual occupants, they insert a ‘stick’ (jemmy) into the door, effect an entrance, and then ‘turn the place over.’.
1937		E. Raymond Marsh 126: If it’s not screwin’, it’s parlour-jumpin’ or dippin’ the lob.
1938		(ref. to 1910s) F.D. Sharpe Sharpe of the Flying Squad 170: One section of these fellows were known as ‘Parlour Jumpers.’ They went round knocking on doors until they found a temporarily unoccupied house or flat, when they would force a way in and collect everything of value.
1949		Monteleone Criminal Sl. (rev. edn).

see fore-room n.