Green’s Dictionary of Slang

1. a worthless, shabby person.

1672		M. Atkins Cataplus 55: Aeneas in time long past knew / This shake-bag as well as I know you.
c.1698		B.E. Dict. Canting Crew n.p.: Shag-bag a poor, shabby Fellow.
1725		New Canting Dict. [as cit. c.1698].
1735		Dyche & Pardon New General Eng. Dict. n.p.: Shag-Bag A poor, shabby, mean-spirited, ragged Fellow.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1743		Fielding Life of Jonathan Wild (1784) II 176: There were particularly two parties, viz those who wore hats fiercely cocked, and those who preferred the Nab or trencher hat, with the brim flapping over their eyes [...] the latter went by the several names of Wags, Roundheads, Shakebags, Oldnolls.
1744		Dyche & Pardon New General Eng. Dict. (4th edn).
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Shag bag, a poor sneaking fellow; a man of no spirit: a term borrowed from the cock-pit.
1796		Grose Classical Dict. of the Vulgar Tongue (3rd edn) n.p.: Shag bag, or shake-bag, a poor sneaking fellow; a man of no spirit.
1811		Lex. Balatronicum [as cit. 1796].
1839		Crim.-Con. Gaz. 6 Apr. 105/1: I saw Dr King [...] giving his left hand to a friend [...] your friendship, old shakebag, is all over the left as ususal.
1946		P. Larkin letter 15 Jan. in Thwaite Sel. Letters (1992) 113: John Heath-Stubbs is reading some of my poems at a meeting of shagbags in London next Friday.
1952		K. Amis letter 4 Oct. in Leader (2000) 294: C is a fearful shagbag.

2. attrib. use of sense 1.

1823

‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 157: ‘A shake-bag fellow,’ if he be no pick-pocket, is at least a seedy cove.