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.
Snazzy is an American slang term. Its origin is unknown. Some dictionaries suggest that it derives from a portmanteau mixture of snappy and jazzy. Others like it to a vaudeville entertainer called Snazelle, whose nickname was Snazzy.
Daniel Cassidy, in his etymological hoax, How The Irish Invented Slang, claims that it derives from the Irish word snas, meaning polish. This is not impossible and it is a very old folk-etymology in Ireland, dating back a long time before Cassidy. The earliest reference I have found to it so far is this, in an article by Seán Mac Labhraí called The “English” Language in Ireland, which was published in a local history magazine in Poyntzpass in 1990:
This article gives the phrase: She was wearing a very snazzy (snas = shine) rig-out.