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 English word smudge is regarded by the Oxford English Dictionary as ‘of obscure origin’ and that it really comes from the Irish smúid or smúit, which he defines as ‘dirt, grime; stain; smoke, soot’.
It is true that the mainstream dictionaries say that its origin is obscure but it has been in English for a very long time, certainly long before there were any communities of Irish-speakers (or English-speakers) in the New World. It occurs first in the early 15th century in the form of smogen, to soil, stain, blacken. The noun meaning a stain, spot, smear is a quite late development from the verb, first attested in1768.
Cassidy’s definition of smúit is not as given in any dictionary. He has rearranged the meanings so that dirt is the principal meaning and also added stain, which is the main meaning of smudge but not mentioned in the Irish dictionaries. Ó Dónaill defines smúit as smúit, 1. Smoke, vapour; murkiness, mist 2. Gloom; morose, despondent, look 3. Dust, grime.
Dinneen defines it as: smúid, -e, f., smoke, vapour, fume, mist, fog; dust, defect; sorrow (also smúit).
In other words, smudge is an old word in English and does not derive from an ancient Irish word for smoke.