Green’s Dictionary of Slang

1. chains and fetters worn by imprisoned felons.

c.1698		B.E. Dict. Canting Crew n.p.: Clinkers c. the Irons Felons wear in Goals.
1719		A. Smith Lives of Most Notorious Highway-men, etc. (1926) 204: Clinkers, the irons felons wear in gaol.
1725		New Canting Dict.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1848		Flash Dict. in Sinks of London Laid Open.
1859		Matsell Vocabulum.
1950		Goldin et al. DAUL 45/2: Clinkers. Shackles, especially for fettering the ankles.

2. stairs [creaking stairs or the ‘clink’ of feet].

1904

Marvel 12 Nov. 6: You’ll ’ave to pad the ’oof up the clinkers.

3. (US Und.) handcuffs.

1881		Trumble Sl. Dict. (1890).
1949		Monteleone Criminal Sl. (rev. edn).

4. (Ulster) the testicles [supposedly ‘clinking’ testicles].

1993

(con. 1945) S. McAughtry Touch and Go 155: Show me your whanger and I’ll tell you what age you are by the number of wrinkles in your clinkers.