Bernhard--
You know, I have wondered that for almost 30 years--
I tried to spell the word as I hear her say it. It could be an "o" instead of an "a", and an "s" instead of a "z." In fact, we actually pronounce it with an "s" sound instead of a "z."
So ousado might be right. Really, as best she can explain what it means, it can be applied to a precocious child.
"Daring", you say? Perhaps stretch that to mean "audacious" -- or, in common parlance, "a handful"? Or even with a suggestion of our slang word, "brassy"?
The way she uses the term is not very complimentary. She does not have much formal education, so to expect her to spell it accurately -- probably not.
I think you may have hit it, although in the "giria" (street language) of Brazil, I suspect the word has other overtones such as I've outlined above.
It appears you know Portuguese pretty well.