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, in his etymological hoax, How The Irish Invented Slang, claimed that the expression stiff, as in ‘a working stiff’, derives from the Irish staf, which he defines as ‘a burly person, a strong, husky, muscular person; fig. a worker. Staf an bais (pron. staf an bash), the stiffness caused by death.’
Dinneen defines the word staf as: a staff (E. R.); a stiff, staff-like person (Ker.).
Ó Dónaill defines it as: staf, m. (gs. -aif).1. Stiffness. 2. Staff, pole.
In other words, all the stuff about burly, muscular people and workers is made-up nonsense. Staf is a borrowing of the English word staff, as in a stick, and it also seems to be partly conflated with the English word stiff. Stiff is probably the genuine origin of the expression ‘working stiff’. We can also see clearly here how limited Cassidy’s knowledge of Irish was. The Irish for ‘of death’ would be ‘an bháis’ (pron. an waash), of course.