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.
Cassidy claimed that gilpin or gulpin, word for a lout in American English, comes from the Irish guilpín, which means a lout.
In fact, there is no doubt that gulpin is a Scots word which entered into Irish and also into American English.
Here is the relevant entry from the Concise Ulster Dictionary from the OED:
(Scots gilpin, gulpin; possibly a form of galopin “a servant boy”, from French galopin, a servant boy.)