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.
Scholars have quite rightly identified that this word is Germanic in origin and is linked to the Middle Dutch word busen, which meant to drink to excess. Booze is a long-established word in English, both as a verb and as a noun. For example, searching on the Michigan Middle English Dictionary website, I found this, from around 1325: Hail, ȝe holi monkes … Late and raþe ifillid of ale and wine! Depe cun ȝe bouse. (Hail, you holy monks. Late and early filled with ale and wine! Deep can you booze.)
Cassidy disagrees and claims that word is first found in English in the 16th century and derives from an Irish word beathuis. You will search in vain for this word in the dictionary. Beathuis is not a real word. Even if it were real, it wouldn’t sound much like booze. It would be pronounced as bahish. While beathuis does not exist, there is a word beathuisce (life-water) in the dictionaries. It is a variant of the vastly more common uisce beatha (water of life) which is the origin of English whisk(e)y. It is pronounced bahishka. According to Cassidy, beathuisce was shortened to beathuis. He gives no evidence of this or reason for it.
He also tries to rubbish the derivation linking it to words in German and Dutch, in a pompous attempt to demonstrate that real linguists and scholars are fanciful and lacking in common sense. ‘There are no modern Dutch or German words resembling busen or bausen, except the German busen, a woman’s bosom.’ No, just as there is no English word bowsen or bousen now, because it has changed into booze, the Middle Dutch busen has changed to the Dutch word buizen, which means to booze or to drink heavily. https://en.wiktionary.org/wiki/buizen
Another problem with Cassidy’s fake version is that the phrase uisce beatha is first recorded in Irish (as uisce bethad) in annals in the year 1405, eighty years after the reference to boozing monks in English above. The ‘water of life’ (aqua vitae) of course is the product of distillation. It is not appropriate in reference to beer, wine or other non-distilled drinks. It is doubtful whether distillation (and phrases like uisce beatha) actually existed in northern Europe when the word bouse was first used in reference to heavy drinking in England.
In other words, there is absolutely no chance that Cassidy’s made-up word beathuis was the origin of the English term to booze.