The "hu-/du-" opposition meaning "good/bad" appears in a number of compounds. Most of the time, these compounds are appended with š - as in "hušiti-", "good dwelling" or the Modern Persian word "došmand", "enemy."
However, I've seen in Sanskrit a potential sandhi combination H->r, as in "Duryodhna" < (duh: + yudh-) meaning "bad/dirty fighter."
With that in mind, is the word "draoj-/draug- ", meaning "lie," really a combination of duH + aoj/aox to mean "bad word/bad utterance"? Looking only at the Modern Persian "durugh" would lead one to that conclusion, but the Avestan and Old Persian forms didn't have that epenthesis. Is there such a thing as a "zero grade" version of duH that became "dr"?
It's interesting how that word seems to have permeated the Balkans, e.g. Serbo-Croat, Turkish, etc. How far north did it go into Slavic? Is it also in Hungarian?