Green’s Dictionary of Slang

(UK Und.) a child.

1648		Dekker Canters Dict. Eng. Villainies (9th edn) n.p.: Lullabie-Cheat, a Child.
1665		Head Eng. Rogue 39: So we had every one his Doxie or Wench, who carried at her back a Lullaby-cheat, and it may be another in her Arms.
1685		New plot newly discovered 7: A walking Mort is one that hath had several lulaby-Cheats, or Children, yet never married.
c.1698		B.E. Dict. Canting Crew n.p.: Lullaby-cheat c. a Child.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1809		G. Andrewes Dict. Sl. and Cant.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1835		G. Kent Modern Flash Dict.
1839		(con. 1703) W.H. Ainsworth Jack Sheppard (1917) 20: My stars! here’s a pretty lullaby-cheat.
1848		Flash Dict. in Sinks of London Laid Open.
1859		Matsell Vocabulum 52: lullaby kid An infant.
1895		C. Crowe Aus. Sl. Dict. 47: Lullaby Kid, an infant.
2023		R. Milward Man-Eating Typewriter 32: A bona fide untamed, untainted lullaby-cheet.