"olasz" has Slavic origins, as I've just learnt. it comes from the south-slavic "vlasi" (=italian), through this transition: vlasz > ulasz > olasz. you can also say "talján" for Italian, but only a few people will understand this word, it is used so rarely...
"Vlasi" was originally not used for Italians, but for romance (latin) -language speaking nations of Balkans, that means mostlyRomanians and Vlachs.
The Polish word for Italians is "Włosi". It must be connected with "vlasi". And it has a similar etymology: "Wołosi" means Vlachs.
You should be able to recognise at least the rosz in oroszok - I believe that's related to the Rus/Ros of Russian, russky, Rossiya, etc.