Green’s Dictionary of Slang

1. a sleep.

1754

Scoundrel’s Dict.

2. as long lib, death.

1612		Dekker ‘Canting Song’ O per se O O2: Bein darkmans then, bouse, mort, and ken / the bien coue’s bingd a wast; / On chates to trine, by Rome-coves dine / for his long lib at last.
1665		Head Eng. Rogue [as cit. 1612].
a.1674		‘Canting Song’ Head Canting Academy (1674) 23: [as cit. 1612].
1688		R. Holme Academy of Armory Ch. iii item 68c: Canting Terms used by Beggars, Vagabonds, Cheaters, Cripples and Bedlams. [...] Long lib, long lying, last end.
1707		J. Shirley Triumph of Wit 196: [as cit. 1612].
1753		J. Poulter Discoveries (1774) 42: Mill the Cull to his Long Libb; kill the Man dead.
1786		Whole Art of Thieving [as cit. 1753].
1799		‘Cant Lang. of Thieves’ Monthly Mag. 7 Jan. n.p.: Mill the Cull to his long lib, Kill the Man you rob.