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.
Daniel Cassidy claims that the English word brag, meaning to boast, comes from the Irish word bréag, meaning a lie.
According to Cassidy, “The Barnhart Dictionary of Etymology speculates that the word brag might possibly have an Irish origin, though inexplicably links it to a Celtic word meaning trousers: ‘brag … of uncertain origin; possible sources include Gaullish [sic] or Celtic ‘braca,’ (a) kind of trousers …’ Barnhart also cites Provencal, French (Swiss dialect), Scandinavian and Old Icelandic as other possible sources of brag.”
I don’t have a copy of Barnhart, so I can’t confirm or refute Cassidy’s interpretation of what it says about this word here, though I suspect that Cassidy has doctored the facts to suit his argument.
Anyway, the facts about the word brag are well-known and beyond doubt. The verb brag is well attested in English as far back as the 14th century, which means that it didn’t come from bréag and has nothing to do with Irish slang in America. For example, the Michigan Middle English Dictionary has this, written around 1400 in the poem Piers Plowman:
He bosteth and braggeth with many bolde othes. (He boasts and brags with many bold oaths.)
The ultimate origin of this verb brag is unknown, though possible sources are a Middle English adjective meaning proud or ostentatious which is probably of Celtic origin or an Old Norse word bragr “the best, the toast (of anything).”
The Irish bréag means ‘a lie’. It doesn’t mean the same thing as bragging or boasting. There are a number of expressions for bragging in Irish: ag déanamh mórtais, ag braigeáil (a loan word from English brag!), maíomh a dhéanamh as rud, ag déanamh a mhór díot féin and half a dozen others.
In addition to brag, English also has a word braggard or braggart, which comes from a French word braguer, which does (probably) come from a word of Celtic origin meaning breeches. (I suspect that the omitted piece in Cassidy’s treatment of Barnhart above probably includes the end of the piece on brag and the beginning of the piece about braggart. Thus Cassidy’s truncated version suggests that the reference to trousers refers to the verb brag, not to the noun braggart.) In spite of the fact that braggart and brag are related in meaning and similar in sound, they are apparently not connected at all etymologically. Coincidences like this are more common than you might think – the best example is probably English dear and Irish daor, almost identical in sound, both meaning expensive, but completely unrelated.