From www.takeourword.com, issue 50
Almost any word that ends with -een can be assumed to
be Irish and smithereens is no exception. The -een
suffix represents the Irish diminutive -ín as in colleen "a
young girl", boreen "small road" or "lane", kippeen "a
small stick". A smithereen is a smidirín in Irish. The only
problem with this is that Irish has no word smidir.
Smidirín is thought to be the diminutive of the English
word smither, a word with no known origin which means
just the same as smithereen.