was a counterfeit coin in circulation in Ireland after the regular coinage had ceased in 1696. The nominal value of the Rap was a half-penny, but intrinsically it was not worth even a farthing.
Swift, in his Drapier's Letters, 1724 (i.), says "Copper halfpence or farthings . . . have been for some time very scarce, and many counterfeits passed about under the name of raps."
The expressions "not worth a rap," " care not a rap," etc., can be traced to the insignificant value of this coin.
R. Twiss, in his Tour in Ireland, 1776 (73), lias: "The beggers . . . offering a had halfpenny, which they call a rap;" and John Wilson, iii Noctes Ambrosianae (i. 282), mentions "Ane o' the bawbees o' an obsolete sort . . . what they ca' an Berish rap."
Byron, in Don Juan (canto xi. 84), says: "I have seen the Landholders without a rap."
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)