Surely you'll not find this word in your dictionary. Why? Because of the same reason you'd not find were in an English dictionary.
Have you an idea of what this word is? Let us suppose you haven't.
Then, would this word be alike to be a PIS-t word, that is to say a word which took at a time a prefix, an infix and a suffix?
If so, then the root letters would probably be חדש: this is a well known root having the basic meaning "new" or "to be new".