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 claims that the word darn comes from the Irish phrase dothairne air. This word does exist, but it is quite obscure. Ó Dónaill’s dictionary has this:
dothairne, f. (gs. ~). Affliction. Díth is ~ ort! Bad scran to you!
Dinneen has this:
dothairne g., id., f., evil, mischief; misfortune; do dhíth is do dhothairne ort, misery and misfortune attend thee.
However, “dothairne air” is not a common expression in Irish. I have just put it into Google and got 8 hits, all of them relating to this blog. The phrase “damnú air” got 489 hits.
There is no doubt about where darn it really comes from. It is first recorded (in America) in 1781. Early references include specific claims that darn is a euphemistic substitution for damn. The existence of expressions like ‘gosh darn it to heck!’ and ‘darnation’ leave us with little room for doubt that this is another minced oath, like Baloney! or Gee Whizz! or Holy Cow!