My paternal grandfather is the oldest person I know anything about who had the name. He was born in Rosiska (the obituaries disagree about whether that is in Czechoslovakia or Ukraine). He passed away before I was born so this is about the extent of my knowledge about him that's relevant to genealogy.
It seems that most immigrants romanized it as "Sczmoniak", but my grandfather did it as "Shimoniak" instead.
An ancestry DNA test leaves open the possibility that it may be Jewish.
In my experience, identifying the town from which your ancestor came might make easier to understand the original spelling (assuming that you can then track down documents for the town). Following this approach, I looked for Rosiska in The Geographical Dictionary of the Kingdom of Poland and other Slavic Countries. Unfortunately, there is no entry. Since I could not find the name directly, I scanned the dictionary looking for towns that could conceivable be mistranslated into Rosiska. For instance, there is a town Rojskoce in Bessarabia. In this vein, you should be aware that the Polish adjective for Russia is Rosyjska, so Rosiska could be a mistranslation.
h, notz) or even Schimoniak – bytebuster Feb 16 '17 at 16:52