Green’s Dictionary of Slang

lackin n.

also laken, lakin
[ety. unknown]

a wife.

[UK]W. Newton Secrets of Tramp Life Revealed 8: Lackin ... A Wife. [Ibid.] 17: If he has a ‘Lakin’ or wife. [Ibid.] 19: Hawkers [...] will give their license or ‘Docket,’ to their wife or ‘laken’.