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.
The late Daniel Cassidy’s bizarre claim in relation to this word is that lulu comes from the ‘Irish’ liú lúith. Liú is a word in Irish for a shout. It’s not the most common word in Irish for that concept. Scread or scréach would be far more common, but it does exist. As for lúith, it’s the genitive of lúth, which means vigour, agility, or tendon. It used to mean ‘joy’ in Irish as well but hasn’t for hundreds of years. Cassidy’s “a vigorous yell of joy” uses two separate meanings, one current and one obsolete. This is a little like saying that a fry can mean “a meal of young fish cooked in oil” or that play is “a dramatic game” because it can mean both play and a drama. This is bizarre and reveals a staggering stupidity and ignorance of how languages work on Cassidy’s part.
Anyway, according to Cassidy, in addition to meaning “a vigorous yell of joy”, it also figuratively means “a complete scream, a howler.” As it is a completely made-up expression, it doesn’t have any “figurative” meanings and there is no evidence of anyone ever using liú lúith for any purpose in Irish.
In reality, a lulu probably comes from the name of a certain Lulu Hurst: