Green’s Dictionary of Slang

1. to steal, to pilfer; to poach.

1865		Derby Mercury 17 May 8/3: The defendant [...] said he knew nothing about it [...] through his being with some men ‘snigging’ pike on Easter Monday.
1879		Edinburgh Eve. News 1 Nov. 3/5: Lord Chief Justice: What did the prisoner say — for ‘snigging’ the mutton? — The Constable: No, my lord — ‘sneaking’ the mutton (Laughter).
1882		Wigton Advertiser 18 Nov. 4/3: Mention was made of illegal fishing [...] a very common practice of ‘snigging’ fish.
1892		Kipling ‘Loot’ in Barrack-Room Ballads (1893) 171: If you’ve ever snigged the washin’ from the line.
1897		Carlisle Patriot 19 Nov. 5/4: Charles snatched at a salmon, and his son had the gaff. Witness [...] charged them with ‘snigging’.
2003		McGill Reed Dict. of N.Z. Sl. 194: snigged home To be wrapped up or pulled into place. From logging term ‘snig’, to drag a log.

2. to drag, to pull.

1877

Burnley Advertiser 22 Sept. 3/5: Fletcher said he saw the officers ‘snigging the women out — [...] He saw the police ‘shoving’ the defendants.

3. in fig. use of sense 1.

1892

Scotsman 18 July 10/5: There has been a large amount of Irish historical stew served up for the snigging of Protestant opinion.