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.
Coon, of course, is an offensive term for a black person. There is some doubt about its origin. Douglas Harper gives a succinct account of the known facts here: https://www.etymonline.com/word/coon
There are two main theories. One is that it comes from the word barracoon, which was in use by 1837, from Portuguese barraca “slave depot, pen or rough enclosure for black slaves in transit”. The other theory is that it was a contraction of raccoon.. Harper points out that one of the lead characters in the 1767 colonial comic opera “The Disappointment” is a black man named Raccoon, which is also a possible source.
Cassidy claims that it comes from the very obscure Irish word cúán, which is given in Dinneen’s dictionary with the meaning “a quiet, backward person”. Cassidy adds to it the ‘figurative’ meaning of ‘a hick’, though this is not derived from any source apart from Cassidy’s imagination. Cúán does not sound like coon (it would be pronounced koo-ahn or koo-awn) and the shortenings of barracoon or raccoon make much more sense.