Language learning is about being able to make your own sentences, not learning the cookie cutter curriculum people give you. By no means use Duolingo as your only source for learning Hungarian. I'd recommend Teach Yourself and Colloquial Hungarian.
rossz also can mean sick. it seems to me that the subject pulls as much for that definition as the one they accept. anyway in view of the wide lexicographic range of rossz, why would they reject any that fit? is there something specifically wrong with sick in this case?