Green’s Dictionary of Slang

dicky n.⁷

a word.

1893		P.H. Emerson Signor Lippo 59: Though they offered me lots of money to blow the gaff, I felt afraid to palarie a dickey for fear of being trapped by either the owner or trainer.
1943		M. Harrison Reported Safe Arrival 61: ’E looked ’e looked the blessed part, I give yer my dicky.
1995		J. Cameron Vinnie Got Blown Away 50: Couple of minutes she never said a dickie. [Ibid.] 71: Never heard a dicky.
2001		M. Coles Bible in Cockney 20: Remember this dicky?