I do I know 'od' means from and not for in the context of this sentence?
'We are buying eggs for this man' would be 'Kupujemy jajka dla tego mężczyzny'.
Maybe it's just me, but I don't hear the 'k' at the beginning, and the p sounds like a b. I just hear 'ubujemy'.
What case of meżczyzna is "meżczyzny"? Accusative? Duolingo doesn't telle unfortunately...
It's in the genitive case. Words following 'od' are in the genitive, which changes a final 'a' to 'y', or in some nouns 'i'.
Który sprzedaje swoje jajka?
So, how would you say "We are buying eggs from these men"?
"Kupujemy jajka od tych mężczyzn".