Quote Originally Posted by bublinka View Post
I think you may be right in your etymology, but as far I as understand language development processes it is very difficult to get that sort of things correct. Even if I know the meaning of "из" and "боина" (from the words like "выбоина", "пробоина") I cannot guess the meaning of "избоина".
Discouraging that we cannot try to guess by putting (what we know) together about the roots. It is all we (non-native Russian students) have to go by when we encounter a new word.

Thanks for being honest with me.