For some time now, some of my on-line friends have advised me to provide a version of CassidySlangScam without the invective aimed at Cassidy and his supporters. In response to that advice, I am working on providing a glossary of the terms in Cassidy’s ludicrous book How The Irish Invented Slang with a short, simple and business-like explanation of why Cassidy’s version is wrong.
The late Daniel Cassidy, in his etymological hoax, claimed that English terms like puck for a spirit (as in Shakespeare’s A Midsummer Night’s Dream) are derived from the Irish word púca, a name for a kind of spirit well-known in Irish folklore. While there is no doubt about the word puck and the word púca being related (and discussion of this goes back a long way before Cassidy) there is little room for doubt that the ultimate origin of these terms is the Norse puki, meaning an imp. Remember that there are no native Irish words beginning with the letter p about from pus, which is a corruption of an earlier word bus.