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.
These three words are clearly closely related, which is why I have chosen to put them together. Cassidy treats them as three separate words, with separate origins in the Gaelic languages.
Before I look at Cassidy’s claims, let’s just look at these three words and their genuine origins. The original word is hackney. This is almost certainly from the place outside London. It is first found in English around the year 1300. It was used to refer to an ordinary horse, in other words, a horse that was not a military horse or a carthorse and then a hired horse, and later, it came to refer to a type of carriage and then to a cab or taxi. Its etymology is discussed here: https://www.etymonline.com/word/hackney and here: https://en.wiktionary.org/wiki/hackney
You can find information on its use in Middle English here: https://quod.lib.umich.edu/m/middle-english-dictionary/dictionary/MED19807/track?counter=1&search_id=1312830
Hack came hundreds of years later and is a contraction of hackney, with exactly the same basic meanings. From the meaning of ordinary, hired-out horse, hack came to mean both a prostitute and a jobbing writer churning out writing of a low standard as well as the meaning of carriage or taxi found with hackney as well. You can find more information about its etymology here:
Hackie seems to be the word hack (in the sense of cab) with an occupational ending -ie, as in chippie for a joiner. It is a recent US term which first surfaces in the 1950s.
Cassidy’s claim is that these three terms, hackney, hack and hackie, all come from three different Gaelic terms. According to Cassidy, hackney comes from each ceannaich, hack comes from each and hackie comes from eachaí.
This is nonsense. Each ceannaich is given in Dwelly’s dictionary of the Scottish Gaelic language as a phrase meaning a post-horse or hire horse. This term can therefore be traced back in Scottish Gaelic (it isn’t Irish) as far as the 19th century. There is no evidence that it existed any further back than that, and I doubt that there was any transport infrastructure in the Highlands and Islands of Scotland where horses were hired out in the 17th or 16th centuries, let alone earlier, so there would have been no need for the term. Remember that hackney in English dates back to the year 1300, so Cassidy would have needed to prove that each ceannaich is older than that to make a convincing case for a Gaelic origin.
Cassidy claimed that each is an Irish word for horse. It is, but it was replaced in spoken Irish by other terms hundreds of years ago. The usual term in Irish for a horse is capall, while in Ulster Irish we say beithíoch – literally a beast. There is no reason to suppose that hack and hackney are anything to do with any variety of Gaelic. The fact is that the range of meanings of hackney and hack in English is so close that there is little room for doubt that hack is a shortened form of hackney.
Then, as usual, there is the question of pronunciation. As usual, the ‘phonetic’ transcription of the Irish is a dog’s breakfast of old Irish orthography (ċ), Irish phonology (c′) and ad hoc nonsense from Cassidy’s imagination. Cassidy’s pretend version of each as h-a′ċ is both weird and completely wrong. Irish and Scottish Gaelic words that begin with a vowel are not pronounced with a h. And Cassidy obviously doesn’t understand the significance of the ′, which is used to indicate a palatal consonant in Irish phonology. As a is not a consonant, putting this marker on it means nothing. You can’t have a palatal vowel. Also, if you listen to the sound files given here for the word amach, you will realise that the ch sound is not the same as the hard ck of of hack, even in the Munster dialect where it is most strongly pronounced: https://www.focloir.ie/en/dictionary/ei/out
In fact, the word each sounds like the first part of Spanish ajo (without the o) and doesn’t really sound like hack unless you pronounce it like someone from New York who doesn’t speak any Irish at all.