Green’s Dictionary of Slang

1. a man, a fellow.

1608		Dekker Lanthorne and Candle-Light Ch. 1: The word Coue, or Cofe, or Cuffin, fignifies a Man, a Fellow, &c. But differs something in his propertie, according as it meetes with other wordes : [...] a Churle is called, a Quier Cuffin; Quier signifies naught, and Cuffin (as I said before) a Man: and in Canting they term a Justice of peace, (because he punisheth them belike) by no other name than by Quier cuffin, that is to say a Churle, or a Naughty man.
1612		Dekker Canting Song O per se O O3: This cuffin, getting glimmer I’ th’ prat, so cleymed his jockey.
1648		Dekker Canters Dict. Eng. Villainies (9th edn).
1665		Head Eng. Rogue I 48: Cuffin, A Man.
1674		Head Canting Academy (2nd edn).
1688		R. Holme Academy of Armory Ch. iii item 68c: Canting Terms used by Beggars, Vagabonds, Cheaters, Cripples and Bedlams. [...] Cove, or Cofe, Coffin or Cuffin, a Man, a Fellow.
c.1698		B.E. Dict. Canting Crew.
1714		A. Smith Lives of Most Noted Highway-men, etc. I 209: He taught his Pupil a deal of canting Words, telling him [...] Cuffin, a Man.
1728		Defoe Street Robberies Considered 31: Cuffin, a Man.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict.
c.1750–1882		B.M. Carew Life and Adventures.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.

2. (UK Und.) a judge; a magistrate [backform. f. queer cuffin under queer adj.].

1703		Hell Upon Earth 5: Cuffin, a Justice.
1708		J. Hall Memoirs (1714) 12: Cuffin, a Justice.

3. (UK Und.) a prison warder.

1857

in Punch ‘Dear Bill, This Stone-Jug’ 31 Jan. n.p.: In the dayrooms the cuffins we queers at our ease, / And at Darkmans we run the rig just as we please.