Croatian here. You're correct, if you only said the word "spomenik" to anybody from former Yugoslavia, they wouldn't be able to distinguish whether you're talking about precisely those monuments built after WW2, or any other monument built before or after the communist era. Or even, say, Washington monument (In Croatian it's literally called "Washingtonov spomenik"). The word "spomenik" means "a monument" and just that. I was actually surprised to learn that in English the word refers to monuments from a particular location and particular era.
Well, there are other examples - to me, Bohemians are my nation, to English people, "bohemian" describes behavior that used to be seen here (and way overblown in catholic-driven news sources at the time - Prague people were protestant) during the Middle Ages
