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 claimed that the English word teem is derived from the Irish word taom. The word teem in English is similar in meaning to the almost identically-pronounced Irish word taom, which means to empty or bale out. However, in reality, both of these words are ancient in their respective languages. Both English teem and Irish taom are borrowings from some word akin to Norse toema. Neither is a borrowing from the other.
Incidentally, the similarity between teem and taom was discussed in the glossary of Loretto Todd’s 2000 book Green English, so this is a claim made before Cassidy embarked on his etymological hoax.