According to Cassidy, the term ‘spree’ as in ‘a killing spree’ or ‘a spending spree’ derives from the Irish word spraoi. The word spraoi is certainly common in the Irish language and many Irish speakers believe it is an Irish word. It means ‘play’, as in bhí siad ag déanamh spraoi (they were playing). You can also say chuaigh siad ar an spraoi (they went on a/the spree). So, surely this MUST be the origin of spree, right?
Wrong, actually. There is no evidence for the existence of the word spraoi in Irish before the early twentieth century. Like the word craic (ceol agus craic), it is almost certainly a loan word which has become an intrinsic and important part of the language since it was borrowed little over a century ago.
If we look up the word spraoi or any variant of it in Corpas na Gaeilge (a database of over 7,000,000 words from the 17th to the 19th century), we find nothing. The same with eDIL, another online database. And Dinneen, the lexicographer who composed his dictionary in the early years of the 20th century, did not include the word at all. This is odd, as it must have been in use in the language at that stage. He presumably left it out because he didn’t regard it as an Irish word.
In English, or rather Scots, the word is recorded as far back as 1804 with the meaning of ‘a pleasant outing’. Scholars of language speculate that it may ultimately derive from a Scottish Gaelic word which is a cognate of Irish spré (spréidh in the older spelling), meaning cattle, wealth or dowry, but spré isn’t recorded with the meaning of outing, drunken ramble or playing in Irish.
It is just conceivable – just – that the word is an old word in Irish and by an incredible coincidence was never recorded anywhere before the modern era. It seems much more likely to me that it is an English slang term (perhaps of ultimate Gaelic derivation) which has come into the language and been adopted by Irish speakers as their own.
Chance of Cassidy being correct about this: certainly less than 1%.