Green’s Dictionary of Slang

1. (UK Und.) a silver tankard; thus rum clank, a double tankard.

c.1698		B.E. Dict. Canting Crew n.p.: Clank c. a silver tankard.
1719		A. Smith Lives of Most Notorious Highway-men, etc. (1926) 204: Clank, a silver tankard.
1725		New Canting Dict.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict.
c.1750–1882		B.M. Carew Life and Adventures.
1753		J. Poulter Discoveries (1774) 42: I’m a Sneak for Chinks [sic] and Feeders; I’m a Thief for Tankards or Spoons.
1768		(con. 1710–25) Tyburn Chronicle II in Groom (1999) xxix: A Clank A Tankard.
1781		G. Parker View of Society II 176: Clink Rig. Stealing silver tankards, pints, &c. Landlords too readily trust strangers into rooms where they deposit plate.
a.1790		H.T. Potter New Dict. Cant (1795) n.p.: clank or clankers silver tankards or cups.
1809		G. Andrewes Dict. Sl. and Cant [as cit. a.1790].
1811		Lex. Balatronicum.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 51: Clank — silver vessels, spoons, candlesticks.
1837		Disraeli Venetia I 153: Tip me the clank like a dimber mort, as you are.
1848		Flash Dict. in Sinks of London Laid Open.
c.1850		Duncombe New and Improved Flash Dict.
1859		Matsell Vocabulum 19: clankers Silver vessels.
1881		Trumble Sl. Dict. (1890).

2. (UK Und.) a silver plate.

1789

G. Parker Life’s Painter 138: The melting pot receiver, proved his selling the clink to him (naps the bib) and that’s what did him over.

3. (US) a silver dollar.

1927

C. Samolar ‘Argot of the Vagabond’ in AS II:9 390/1: A dollar, a clanker or slug.