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.
Cheese it is an old flash (criminal slang) expression meaning to shut up or to stop what you’re doing. There is no clear derivation. The phrase is discussed in detail here: http://www.worldwidewords.org/qa/qa-che4.htm
Daniel Cassidy, in his work of false etymology, How The Irish Invented Slang, claims that it comes from the Irish téigh as, which he defines as follows:
“Téigh as (pron. chéɣ’as), go away from; flee from; get out of, escape. Ná téigh as láthair, don’t absent yourself. Go out, extinguish, stifle (as sound); fig. shut up.”
In fact, téigh as means the following, according to Ó Dónaill’s dictionary, Foclóir Gaeilge-Béarla:
téigh as, v.i. 1. Go away from. 2. Go out of. 3. Go beyond. 4. Fail. 5. (Of light, etc.) Be extinguished. 6. Get out of.
In other words, if you are talking about a candle going out, you could say chuaigh an choinneal as, just as you would say in English ‘the candle went out’. However, this is intransitive. It means to go out spontaneously, not to extinguish or stifle, and it cannot be applied to sound. It has no figurative meaning of ‘shut up’. Cassidy is simply distorting the meanings of the Irish phrase in order to make it sound like a good candidate.