Well the Ferengi were a largely unknown race when first encountered in TNG, beyond the fact they were hyperlibertarians they didn't bother elaborating. They wer

Well the Ferengi were a largely unknown race when first encountered in TNG, beyond the fact they were hyperlibertarians they didn't bother elaborating. They were the portrayed as an annoyance more than anything serious to worry about. DS9 was the first series to really build on it, and they recycled a lot of old rejected b plots from TNG in the first couple of seasons so there was a lot of filler dialog which became canon.