Another really stupid claim made in Daniel Cassidy’s book is that the expression ‘darn it’ comes from Irish.
Why is this stupid? Well, for one thing, 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!
Cassidy ignores the logical explanation and claims that it comes from 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.
Unusually, Cassidy’s definition is not too far from Dinneen’s and Ó Dónaill’s. In this case, Cassidy has resisted the temptation to add any ‘figurative’ meanings from his own imagination.
The problem is this. If we put “dothairne air” into Google, we get no hits at all. If we put “damnú air” into Google, we get (well, today I got) 1360 hits. So, dothairne is not as common in Irish as Cassidy would like us to believe and of course, Cassidy didn’t speak Irish and knew nothing about the language.
Incidentally, there is a variant of this which gets a handful of hits on Google, the fake word ‘daithairne’. This comes from a singularly dim-witted article by Brendan Patrick Keane on IrishCentral, where Keane was apparently too lazy to copy the word out from Cassidy’s book properly, and too stupid and ignorant of the Irish language to realise that daithairne violates a basic rule of Irish orthography, caol le caol is leathan le leathan. (It would take too long to explain this properly, but basically, consonants have two values depending on whether they are next to an i,e or an a,o,u. For example, in mise, pronounced misha, the s is slender because it has an i and an e next to it. In measa, pronounced massa, the s has an a before it and after it, so it’s broad. The –aithai- string is strange in Irish because it’s slender on one side and broad on the other.) Still, at least this is on IrishCentral where it will hardly be noticed. A little more rubbish there will be like mún dreoilín san fharraige (a wren pissing in the sea.)
Incidentally, dang it (which Cassidy’s razor-sharp intellect somehow missed) might just have an Irish connection. In Irish, damnú air (damn it) is sometimes disguised as daingniú air (strengthening on it). It is not impossible that this gave rise to dang it, as there is no word dang in English.