It is the word for Finland in the Finnish language.
The Finnish language is suomi (Finnish) or suomen kieli (Finnish language) in Finnish.
That word is not Finnish.
it comes from Finnish language
Pleb is not a Finnish word.
Tuloo in itself is not a word in Finnish. You might be referring to the word tuloa, which often is pronounced tuloo in spoken language. It is also possible that you mean the word tulee or tulevat that are pronounced tulloo in some dialects.
Sevol is not a word in Finnish. It is most likely that you have misheard a word or thought that parts of two different words were one word. This is quite common when hearing a language you don't understand.
It comes from Finnish language