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.
Daniel Cassidy, in his etymological hoax, How The Irish Invented Slang. claims that the verb ‘to spar’ in boxing comes from the Irish spairn, which means fight, contention, struggle. This is well-known to Irish speakers in the phrase cnámh spairne, a bone of contention.
In order for this to be even slightly convincing, the word spairn needs to have been borrowed into English as sparring and this would then have to have been shortened to spar by the process known as back formation. This is not the case. We find the verb as sparrit, sparres and sparred in Middle English, where it meant to thrust or strike rapidly.
In other words, there is (coincidentally) a similar word in Irish, spairn, but there is an even more appropriate source in English, sparren, which was already in use in colloquial English six hundred years ago.